Using the Doppler radar and AWS data, this paper comprehensively analyzed three gust front processes which took place in Jiangsu Province on 16 May, in Beijing Tianjin Hebei region on 9 June and in Hebei Province on 10 July 2012. It turned out that the thunderstorm high which is formed by the continuous subsiding cold air, is the immediate cause of the formation of gust front. In the formation process of thunderstorm high, on the one hand, cold subsiding air stacks rapidly and forms thunderstorm high in a narrow area; on the other hand, the new monomers constantly replace the old, thus, stable downdraft in the storm develops thunderstorm high. Under the high pressure, strong divergence airflow and ambient air form the gust front. Gust front moves forward and enhances with the movement and enhancement of the thunderstorm high, and gradually disappears when thunderstorm high weakens. The greater temperature gradient and pressure gradient are, the stronger instantaneous high winds and gust front become. Instantaneous high wind speed that gust front produces is not always proportional to the intensity values of narrow band echo. MARC can indicate the emergence of gust front about half an hour, and the longer the convergence maintains, the longer the gust front maintains.