The maternity security system in China has experienced a series of reforms in the last 30 years .At present,two types of social security systems play the functions of the maternity security .One is the maternity insurance system,which provides maternity allowance and medical benefits on maternity to wage earners in state organizations,enterprises,institutions and other economical and social organizations .The other is the new rural cooperative medical system and basic medical insurance for urban residents,which provides rural and urban residents (no-wage-earners) with only partial medical expenses on maternity .Compared with the wage earners,no-wage-earners cannot get compensation in the period of earning interruption . This system has many problems . First of all,there is the problem of″fragmentation .″The participants are graded according to their identities .It's hard to transfer the maternity insurance accounts among different regions,since different regions have different policies .Secondly,there is the problem of a lack of fairness .Differences in the maternity protection benefit are quite remarkable among different classes of participants,with employees in the state organ and institutions the highest,enterprise employees the second and rural and urban residents the lowest .Thirdly,the actual coverage of the maternity security is inadequate .According to the already-established system,all the wage earners should be covered by the maternity insurance .However,the number of the people participating in maternity insurance is much smaller than that participating in the basic old-age insurance and basic medical insurance .Fourthly,operation efficiency of this system is not very high .Sometimes it's difficult to distinguish the maternity insurance item from the expenditure on birth-giving,or other medical insurance items .The responsibility border between the maternity insurance fund and the basic medical insurance fund is not clear . Compared with other social security programs,maternity security receives less attention in both the academic and the practical fields .Some scholars have put forward ideas on how to improve the maternity insurance system .They propose to build a unified system that allows rural and urban residents to have equal access to the benefit,but most of them are not quantitative analysis .There is also lack of specific measures to support the ideas . Following the policy of″making coverage universal,ensuring basic care,and providing multilevel and sustainable social security″and the principle of″establishing a fairer and more sustainable social welfare system,″we should protect the maternity security right of all the people .Therefore,a new maternity security system of universal coverage should be established : ″maternity allowance system″+″maternity medical expense security in the basic medical insurance .″Specifically,the medical expense in the original system should be merged into the basic insurance's responsibility ;the maternity allowance system should be set up to cover all the urban and rural residents,which provides basic income compensation in the period of earning interruption . This paper forecasts the number of people who enjoys the maternity allowance and the size of the fund in the future based on the population forecast model and actuarial analysis model .The results show that the fund needed for the maternity allowance takes up a very small proportion in the government revenue . The medical expense in the original maternity insurance system is suggested to merged into the basic insurance responsibility .The paper reveals the effect of this adjustment on medical insurance fund paying based on the quantitative analysis model . The results show that the contribution ratio of basic medical insurance should be increased by 0.28%-0.35% .In conclusion,the reform of the maternity protection system is essential and feasible .We propose to create conditions and operate the reform step by step .At the same time,much attention should be paid to the comprehensive social effect of the reform .Also,the related issues should be appropriately handled in the period of system transition .