Based on the hourly precipitation data from June to September of 7 national meteorological stations during 1996-2015 and 63 automatic weather stations during 2008-2015 in Taiyuan, and relative radiosonde and surface observation data, the synoptic patterns of circulation configuration on short-time heavy rainfall days in Taiyuan were classified and the characteristics of key environmental parameters under different patterns were studied. The results show that there were four circulation patterns on 500 hPa during short-time heavy rainfall processes in Taiyuan including cold vortex type, upper trough type, upper trough with subtropical high type and northwest flow type. Short-time heavy rainfalls in Taiyuan always happened under weak CAPE, and in most cases it was less than 1500 J·kg-1, and for all of cold vortex type it was less than 1000 J·kg-1. For northwest flow type, the ΔT850-500 was bigger and there always was stronger static instability and obviously dry layer on 500 hPa. For upper trough with subtropical high type, there always was a higher K index, and mean value of warm cloud thickness was 3576 m, which was significantly thicker than those of the other types. The entire cases of cold vortex type and 85% cases of upper trough type happened under weak vertical wind shear within 0-6 km, 35% cases of upper trough with subtropical high type and northwest flow type occurred under a moderate vertical wind shear condition. Cold vortex type and northwest flow type always had better vapor conditions on 700 hPa than that of 850 hPa. The extreme rainfall more than 70 mm·h-1 occurred under northwest flow type, which had moderate CAPE, strong unstable stratification, weak 0-6 km vertical wind shear, and plenty vapor from low to middle layer with warm cloud thickness more than 3550 m, the cooperation of these environmental parameters had denotative meaning for the strong precipitation efficiency.