Abstract: The macro and micro cloud physics structure and their evolution with time are the core of describing cloud fields in essence.They are necessary atmospheric environment not only in aviation and spaceflight activities but also for atmospheric radiation transfer and acid rain formation research.Unfortunately it is difficult to obtain an entire environmental cloud field by using observation methods directly.Thus, by use of computation physics method to build a cloud-system model may be an indispensable way for this topic.This paper presented a cloud-system model for this goal, and simulated a real case.The results of computation showed that the macro structure of the cloud field was better consistent with real observation, and the micro structure was fairly reasonable.The output of model could provide all the information about the cloud field: (1) size-distribution spectrum of hydrometeor particles (point), (2) vertical profile (line), (3) horizontal or vertical section of macro and micro parameters (surface),and (4) cloud cover, pattern of cloud and configuration of cloud, etc. (body).