Abstract: Under the background of the reform of "Decentralization, Regulation and Service", the practice of linking planning EIA and project EIA focuses on simplifying the contents and procedures of the EIA of projects which are included in the planning, but too much attention on efficiency is not conducive to the realization of the risk precaution function of the EIA system. The relevant provisions in current laws, regulations and policies at the national level are relatively principled. In the local practice and exploration, there are major differences in the conditions and ranges of linkage, simplification of content and ways of approval, and the standardized and unified linkage mechanism has not yet been formed. Therefore, based on the construction mechanism of linkage between planning EIA and project EIA, aiming at the problems existing in the present practice, it was suggested that the opportunity should be taken to revise the EIA Law to make EIA return to the original precautionary essence, clarify the applicable conditions and scope of the linkage mechanism, determine the simplified or strengthened contents of the project EIA, respond to the legitimacy doubt about the reform practice of EIA, and establish a bottom-up feedback and supervision mechanism, which could provide a legal construction scheme for the linkage mechanism between planning EIA and project EIA.