Mass spectrometry-based single cell proteomics (MS-SCP) is attracting tremendous attention because it is now technically feasible to quantify thousands of proteins in minute samples. Since protein amplification is still not possible, technological improvements in MS-SCP focus on minimizing sample loss and increasing throughput, resolution, and sensitivity, as well as achieving the measurement depth, accuracy, and stability as bulk samples. Major advances in MS-SCP have facilitated its use in biological and even medical applications. Here, we review the key advancements in MS-SCP technology and discuss the strategies of the classic proteomics workflow to improve MS-SCP analysis from single cell isolation, sample preparation and liquid chromatography separation to MS data acquisition and analysis. The review will provide an overall understanding of the development and application of MS-SCP and inspire more novel ideas regarding the innovation of MS-SCP technology.