With high subsidy and the intervention of local government，Chinese agricultural insurance market has become the second largest in the world. It is estimated that more than 80 billion subsidy has granted to farmers. Therefore， the hedging effect of agricultural insurance on farmers’revenue risks becomes one of the key issues that researchers and policy makers are concerned of. In addition，the performance of agricultural insurance becomes an important index of the efficiency of subsidy. The study investigates the hedging effect of hog insurance on farmers’revenue risks by using farmer-level data. Two-period panel data regression model is adopted to examine whether agricultural insurance can significantly reduce farmers’revenue risks. Standard deviation of farmers’hog revenue is used to measure their revenue risks. Our results would shed light on the performance of Chinese agricultural insurance，pointing out its shortcoming and helping improve agricultural insurance system． Empirical results show that farmers’revenue risks are not significantly reduced after their purchasing of hog insurance. One of the reasons is that the sum insured of hog insurance contract is too low to compensate farmers’losses when an insured event occurs. During the past 5 years，the average revenue per hog is between 1 170 to 1 430 Yuan. However，it is stipulated in hog insurance contract that the sum insured is only 400 Yuan， which is far below the average revenue. Therefore，the indemnity paid by insurers is not enough to compensate farmers’losses，thus the hedging effect of hog insurance is weak. At the meantime，the survey shows most farmers complain that sum insured of hog insurance is too low and some of them are unwilling to purchase hog insurance in the coming year. Most farmers wish the sum insured of hog insurance to be raised. To investigate the hedging effect of hog insurance with higher sum insured，we assume a full coverage contract， which implies that all losses occurred could be covered by hog insurance contract. The results of two-period panel data regression model show that farmers’revenue risks are reduced significantly if farmers purchase full coverage insurance contract. That is， the hedging effect is greatly increased when the sum insured is raised to a level that insurers would compensate all losses occurred． Therefore， raising coverage level of agricultural insurance is one of the reform directions in China， especially under the circumstance that farmers’willingness to pay has greatly increased.On the other hand，it also is a challenge to government and insurers. As far as government is concerned， more subsidies are needed when sum insured is increased while the subsidy rates keep unchanged. As for insurers，higher sum insured may induce more adverse selection and moral hazard which would do harm to insurance company performance. Thus，raising sum insured needs the cooperation of all parties，and could be accomplished step by step.