Abstract: In the process of preparing "SE+PERC" c-Si solar cells,after the positive passivation dielectric film is deposited by the tube type plasma enhanced chemical vapor deposition（PECVD） technology,the red color difference at the corners will appear on the front of silicon wafer,that is,coating uniformity abnormal.This paper takes this as the research object,and through experiments,analyzes and discusses the influence of silicon wafer thickness,the status of tools and instruments,back film structure,deposition process of positive passivation dielectric film,and other factors on the red color difference at the corners of front side of silicon wafers,respectively,and proposes solutions. The research results show that the red color difference at the corners of front side of the silicon wafer is related to the thickness itself,the status of tools and instruments,the back film structure,and deposition process of positive passivation dielectric film. By adopting the most advantageous process conditions,that is,optimizing the automatic chip loading technology,controlling the graphite boat shaped variable,adopting the appropriate back film structure,and using the high RF power and high cavity pressure in the deposition process of positive passivation dielectric film,the proportion of silicon wafers with red color difference at the front side corners can be reduced to 0%,which can effectively improve the yield of "SE+PERC" c-Si solar cells and improve the economic benefits of production lines.