OBJECTIVE： To provide reference for formulating the policy of promoting the popularization and application of essential medicines in second grade or third grade medical institutions. METHODS： Drug purchase and warehousing data was collected from 31 second grade or third grade medicinal institutions in Nanjing during Jan. 2012-Dec. 2015. Excel 2010 and SPSS 20.0 software were used to summarize and analyze statistically the purchase amount of allocation quantity of essential medicines. RESULTS： The proportion of essential medicine purchase amount in total medicine purchase amount during 2012-2015 were 18.33％， 18.56％， 17.19％， 17.53％ in 31 medicinal institutions （called “the ratio of essential medicine purchase amount” for short）； the proportion of national essential medicine purchase amount in essential medicine purchase amount （called “the ratio of essential medicine purchase amount”for short） were 31.14％， 29.40％， 25.69％， 25.79％， respectively. The number of generic names for allocated essential medicines were 189.84， 205.58， 210.26， 206.65， respectively. The ratio of essential medicine purchase amount and the ratio of essential medicine purchase amount in 2014 were decreased significantly， compared to in 2013 （P＜0.05）. The number of generic names for allocated essential medicines in 2013 was increased significantly， compared to in 2012 （P＜0.05）. The ratio of essential medicine purchase amount in second grade medical institutions was significantly higher than third grade medical institutions， the ratio of essential medicine purchase amount in general hospital was significantly higher than special hospital； the number of generic names for allocated essential medicines was significantly higher than TCM hospital and special hospital； the ratio of essential medicine purchase amount in second grade medical institutions with community health service center in subjection to them was significantly higher than those without community health service center in subjection to them； there was statistical significance （P＜0.05）. There was negative correlation between the ratio of essential medicine purchase and total purchase amount of medicine in general hospitals （P＜0.05）. There was positive correlation between the number of generic name of allocated essential medicines and the number of generic name of all medicines in 31 medical institutions （P＜0.05）. CONCLUSIONS： The ratio of essential medicine purchase amount and national essential medicine purchase amount， the numbers of generic names of essential medicines were very different and low in these hospitals during 2012-2015. Just one or two had met the requirements of the Jiangsu provincial health and family planning commission. The grade， type， medicine purchase and allocation scale， administering community health service center all influence the purchase and allocation of essential medicines.