The performance of parallel programs, especia lly the parallel efficiency evaluation, usually needs to get data after running the program. Then through checking the experimental results, the programmer opti mizes the parallel algorithms, modifies data placement policies, or even selects other algorithms. In this paper, based on the BSP parallel programming model, a n evaluation model for predicting the efficiency of parallel programs is present ed, which allows programmer to evaluate the efficiency at the stages of algorith m design and programming, and then take some measures to optimize the programs f urther. The experimental results show that the evaluation predication model is a ccurate.