The purposes of this study are to provide a theoretical answer to the question of the causes of popular uprisings under communist rule and to predict the possible methods communist parties may adopt to prevent such uprisings. The author argues that the formation of popular uprisings in communist countries results from the joint effects of structural and catalytic factors. The former causes social discontent while the latter transforms social discontent into political protest. In communist countries, the catalytic factors are either protest activities planned by specific dissident groups or "nonpolitical incidents." Once the Communist Party fails to respond to non-political incidents appropriately, these incidents will trigger popular uprisings under the conditions of lack of resources, leadership, and organ- izational strength. The author then derives the strategies the Communist Party may take to prevent popular uprisings: (1) paralyzing all autonomous social groups, and (2) skillfully responding to all non-political incidents which may cause mass gatherings and then preventing them from turning into political demonstrations.