OBJECTIVE：To improve the willin gness of chinese pharmaceutical enterprises to participate in drug patient assistance programs ，improve the level of drug use and access to innovative drugs in China and fully evaporate the supplementary role of the medical security system. METHODS ：Through grounded theoretical analysis of the interview results ，the theoretical framework of the factors affecting the implementation of drug patient assistance programs by pharmaceutical companies was proposed. The above theoretical framework was empirically studied through questionnaire survey on the personnel who understood or participated in drug patient assistance program in Chinese pharmaceutical enterprises. Based on partial least squares structural equation model ，Smart PLS 3.0 software was used for data processing to analyze the influence of different factors on the willingness of pharmaceutical companies to participate in drug patient assistance programs ，and the relevant suggestions were put forward. RESULTS & CONCLUSIONS ：Economic benefits ，market competition ，social benefits and policy environment have significants impacts on the willingness of pharmaceutical enterprises to implement drug patient assistance programs. The path coefficients were 0.244 （P＜0.01），0.236 （P＜0.01），0.235 （P＜0.05），0.228 （P＜0.01）. Human resource efficiency and cooperation unit have no significant effects on the willingness of pharmaceutical enterprises to implement drug patient assistance programs（P＞0.05）. Economic benefits are in line with the nature of enterprises ’profit-making and have the most close influence. Therefore，the pricing strategy of drugs and the tax policies of government departments are very important for enterprises. Participation in market competition is also an important factor for enterprises to participate in patient assistance programs. The earlier the implementation of patient assistance ，the more opportunities of relevant drugs will be to seize more markets. The social benefits manifest as reducing the economic burden of patients ，improving the quality of life ，and promoting the social and economic development. At the same time ，enterprises have set up good social image and forms a word-of-mouth effect. The policy environment generally includes the legal environment and medical insurance policies. The legal provisions restrict the donations of pharmaceutical enterprises to a certain extent ，but corresponding regulatory measures are still essential. Medical insurance policies are closely related to the establishment and adjustment of patient assistance programs ，and the connection between medical insurance access and patient assistance programs needs to be further improved. Therefore ，from the perspective of enterprises ，it is recommended to establish a cost and benefit calculation system for drug patient assistance programs ，and broaden the publicity channels and increase the publicity intensity of patient assistance programs. From the perspective of the government ，it is recommended that tax incentives for donations should be increased，the patient assistance supervision system should be improved ，the access and adjustment rules for the drugs of patient assistance programs in medical insurance list should be clarified ，so as to promote pharmaceutical enterprises to actively participate in patient assistance programs and improve the drug use level and drug accessibility of patients.