Abstract: Objective To study the changes of all kinds of expenses among psoriasis vulgaris inpatients after the implementation of zero price difference policy in order to provide a better basis for optimization of the policy. Methods Total 749 cases of psoriasis vulgaris inpatients in Shanghai skin Disease Hospital from January 1 st, 2015 to June 20 th, 2017 were selected. The general information of patients and information on total expenses during hospitalization were collected. SPSS 19.0, univariate and multivariate regression analysis were used to analyze the relevant data to explore the impact of general factors and zero price difference policy on various types of costs. Results Univariate analysis showed that medical expenses of males were higher than females(P=0.003), the higher inspection fees of older(P=0.009), the higher various types of expenses of more hospitalization days(P<0.001). The price difference policy had a significant effect on the total cost, drug cost and treatment cost(all P<0.05), but it had no significant effect on the inspection cost(P=0.685). Multivariate regression analysis found that the drug cost had the greatest influence on the total hospitalization expenses. Analyzing both general and zero price difference factors showed that the longer the patients stay at hospital, the higher cost of hospitalization is(P<0.05). In terms of total hospitalization expenses and drug costs, the price difference of 5% and price difference of 10% were remarkably higher than zero price difference(all P<0.05). There was no significant difference between the price difference of 15% and zero price difference(P>0.05). Furthermore, the price difference of 5% was less than the price difference of 10%. In terms of treatment fees, the fees of males were higher than females'(P<0.05), and the price difference policy had no significant impact on the treatment costs. Conclusion The majority of medical expenses among psoriasis vulgaris inpatients show a downward trend after the implementation of the policy, which reduces the economic burden of patients to some extent.