Using the NCEP/NCAR 1°×1° grid data, two of the heavy snowfall occurred in the winter of 2010—2011 in Zhejiang Province were studied. Based on the diagnostic analysis on the circulation over the high and low level, the moisture conditions, the dynamic field and the thermal characteristics and the comparison of the two heavy snowfall, the results indicate that the snowfall on December 15, 2010 was a cooling process with the erection transfer of high-altitude horizontal groove and strong surface cold air blowing southward, meanwhile the snowfall on January 18—21, 2011 was in the cool context with southern branch trough deepening and moving eastward and the warm-wet southwest wind blowing northward, the ground was within the control of cold high variability. At the middle level, for both cases, the augment of the southwester flow exists. Over the low-level, the former water vapor was transported by east jet, while the later water vapor was transported by the southwest air. The two processes require adequate supply of water vapor and vertical ascending motion. Energy front of the former is the southward, while the energy front of latter is a north-south fluctuation. Two processes both meet the basic conditions of temperature field and have the structure of a temperature inversion. However, the former has a strong inversion layer, while the latter is relatively shallow.