OBJECTIVE：To provide reference for improving the equity of medicine in China ，and to provide reference for promoting the full coverage policy for essential medicine. METHODS ：Taking hypertension essential medicines full coverage policy in 4 areas of Taizhou in Zhejiang province as an example ，the electronic health records of patients in baseline year and the first ， second and third years after the implementation of the full coverage policy of hypertension were collected. The catastrophic expenditure of family drugs was used to measure the medicine cost burden ，and the effects of policy on the equity and change of local medicine cost burden were analyz ed by means of concentration index and its decomposition method. RESULTS ：With the increase of the proportion of patients taking free medicine ，the incidence of catastrophic expenditure on household medicines in the high，middle and low income group decreased year by year generally （decreasing from 6.3％，12.0％，16.4％ of baseline year to 4.7％，8.9％，12.4％ at the third year after the implementation of the policy ）；the gap among the three groups was in narrowed trendency. The concentration indexes of the baseline year and the first ，second，third year after the implementation of policy were －0.198，－0.186，－0.181，－0.202，the policy contribution rates of which were 0，－1.335％，－4.507％ and 1.936％；and the policy contribution rates in the change of the yearly concentration index were 20.8％，95.0％ and 57.6％. CONCLUSIONS ：The implementation of the full coverage policy for essential medicines is conducive to improving the equity of the medicine expenditure burden. The effect is affected by the implementation of policies and supporting systems ，but the comprehensive promotion of the equity of medicine requires multi-policy synergy.