Abstract: Objective To explore influencing factors of medication compliance among chronic disease patients under the implementation of national essential medicine system.Methods A total of 1 200 chronic disease patients in Shandong province were recruited with stratified random sampling and surveyed with 8-Item Morisky Medication Adherence Scale.Univariate and multivariate analysis were used in data analyses.Results Among the participants,the awareness rate of national essential medicine system was 50.7% and the proportion of the participants with good medication compliance was 63.8%.The proportion of the urban participants with medication compliance was higher than that of the rural participants (64.3%222/345vs.63.5%543/855);compared to the participants in developed regions,the participants in undeveloped regions showed a higher proportion of medication compliance(66.1%517/782vs.59.3%248/418);the participants aged less than 40 years had a higher proportion of medication compliance than the participants at other ages (71.6%96/134vs.62.8%669/1 066).The influencing factors of medication compliance included participants'medication preference,medicine supply and medication guidance in grassroots medical institutions.Conclusion Top-level design optimization of national essential medicine system should be implemented and measures should be taken to adjust medication preference of chronic disease patients and to promote medication guidance in grassroots medical institutions.