The invention discloses a GPU (graphics processing unit) based software system architecture and a UML (unified modeling language) and ADL (architecture description language) combined describing method and belongs to the technical field of software system architectures. The GPU based software system architecture is characterized in that a pipeline and filter mode is applied to modeling, filters include a data stream preprocessing filter, a data stream relief filter, a CPU (central processing unit) loading engine filter, a GPU loading engine filter, a data stream processing filter and a visual filter, original data streams sequentially pass the data stream preprocessing filter, the data stream relief filter, the CPU loading engine filter, the GPU loading engine filter and the data stream processing filter through a pipeline, the data stream processing filter transmits data results to the GPU loading engine filter and the CPU loading engine filter in succession, and the CPU loading engine inputs the data results into the visual filter. UML and ADL are used together, advantages of the UML and the ADL are combined, and the GPU based software system architecture is better established.