Abstract: Analyzing protein expression at the single-cell resolution is of crucial significance for exploring cellular heterogeneity and tumor microenvironment, and advancing basic biological research such as clinical precision medicine. With the advancement of material chemistry, nucleic acid chemistry, protein chemistry, as well as the iterative upgrading of new detection equipment and data processing systems, single-cell protein detection techniques have developed rapidly. Among them, single-cell protein detection techniques based on immunoassay, with their good targeting ability and wide applicability, have become important means for single-cell protein analysis. This article reviews the principles, advantages and disadvantages, as well as the applications of single-cell protein detection techniques based on immunoassay, with a prospect of the development trends of single-cell protein analysis technology.