Reports of the 19th National Congress indicates that it is necessary to fully establish a multi-level social security system that features the universal coverage，overall urban-rural development，right-duty clearing，moderate level and sustainability，and an essential part of it is the system of elderly health care service. Optimizing the supply structure of elderly health care service and improving the supply capacity of that are the cornerstones of the construction of the system of elderly health care service. This study focuses on the supply side reform of elderly care service to figure out the situations and problems in which the public and private supply of Beijing public elderly care service is lying. The study also explores the appropriate elderly care service mode in accordance with the characteristics of Beijing the capital from three aspects：strengthening government regulation，problems solving accurately，the improvement for the quality of the personnel.