Micro total analysis systems (microTAS) also referred to as "lab-on-a-chip" is one of the fastest progressing fields in biological and chemical analyses. In recent years, microTAS for single cell analysis has drawn the attention of researchers due to its significant advantages over traditional methods for single cell manipulation, fast cell sorting and integration of multiple functions. As the preliminary step for studying cells on chips, cell sorting using microfluidics have been investigated by researchers intensively. This article reviews the most recent advances on microfluidics-based cell sorting techniques including cell sorting principle, strategy, mechanism and procedure with emphases on the sorting mechanism and procedure. Furthermore, evaluation criteria for successful cell sorter are also discussed and future research directions are given.