Integrated microchemical systems on microchips, which are based on continuous microflows, are expected to become important tools for analysis and chemical synthesis applications for biological sciences and technologies. For these purposes, general integration concepts have been developed, including microunit operations (MUOs) and continuous-flow chemical processing (CFCP) to create fully functional systems for various chemical processing applications. The general methodology has enabled analysis, synthesis, and fabrication of chemical systems on microchips, and these microsystems have demonstrated superior performance (e.g., rapid, simple, easy operation, and highly efficient processing) compared to conventional methodologies. Microchemical technology has now entered the phase of practical application. In this review, we discuss the methods for integration of continuous flow-based chemical process on microchips, relevant technologies, and applications.