Sweatshops in developing countries have been highly condemned by consumers from developed countries. Corporate social responsibility movement and competition in the market have prompted more and more companies in developing countries to become a part of the labor certification of the supply chain. Since Labor standards which have been transplanted by means of trading platforms have had some impacts on the Chinese labor conditions and labor legal systems，the field investigation found that the impacts were still at the early stage. As buyers and sellers can not agree on product-related information under asymmetry information，labor standard is like a signal, which can determine the share and efficiency of both transactions through its transmission and screening. Based on the sellers-led market structure，this paper uses signal model to analyze situation of labor standards transplant in China. The study indicates that: （1）The level of suppliers’ labor standards tends to be minimum due to the results of Pareto improvement by the suppliers with their market forces；suppliers (or manufacturers)must bear the cost of signals while transmitting them, so there will be distribution of resources distorted compared to the original configuration. And as the recipients of signals，buyers screen signals on different posterior probability，and offer different prices according to recognition of the signals and form a self-confirmed multiple equilibrium. Rational suppliers who maximize individuals income under seller-led market structure adjust the equilibrium price signals to achieve Pareto optimality through the market mechanism step by step，thus showing a lower labor standard. Finally it leads to a fully-confirmed equilibrium，which is also more stable one. （2）If the distribution function of the companies types is sufficiently concave，labor standards will converge to the lowest point of equilibrium，not higher than the lowest one. When there are more companies with lower ability，pooling equilibrium of minimum standard will be produced. The companies with higher ability will choose to lower labor standards signals, which is the result of collective rationality. When the types of companies present concave function distribution, it means that the intensity of companies with low labor standards is so high that buyers can gain the lower average earnings. The final equilibrium tends to be the lowest point under the game of buyers and suppliers on circumstance of participation constraints. On one hand buyers can avoid taking the risks of getting negative expected returns，on the other hand there is a pooling and cooperative equilibrium at the lowest point among the companies. When the types of companies present convex function distribution, it means that intensity of companies with high labor standards is so high that the final equilibrium tends to be higher than the lowest one In the long run，the "new" returns brought about under the separating equilibrium tend to be higher than that under the lowest pooling equilibrium. Some companies in developing countries based on seller-led market should take advantage of the opportunities of labor standards transplant to improve labor conditions inherently，allowing labor standards signal to drive product quality for more acceptance of buyers and consumers so as to gain greater market forces.