A snowstorm accompanied with thunder and lightning on November 9, 2009 was analyzed from its smallscale feature. Using observation data from wind profiler, microwave radiometer, automatic weather station, Doppler weather radar and satellite, the fine temporal and spatial structures of this snow case and the causes for the convection in winter were discussed. The results showed that this case is a typical return flow process in northern China. The elevated convection and lightning storms were generated with the warm and moist air from southwest above the lower cold air, and the triggering mechanism for the convection was the disturbance in the middle layer. The results of this case study will be instructive for the winter lightning forecast in snowstorm weather.