Abstract: To investigate the spreading mechanisms and rules of complex network with community structure, two network models with community structure were constructed based on the well-known small-world network and scale-free network． These models permitted different wiring of community structures at individual and group levels． The impact mechanism of community structure characteristics on transmission dynamics was investigated by simulation experiments． Interestingly, the dynamics of epidemic spread in the two above mentioned network models show significantly different evolutions as the modularity changes． Different wiring schemes within and without communities lead to different average path lengths in the network, resulting in different mechanisms of community structure impact on epidemic transmission dynamics．