Abstract: The main weak point of BP algorithm is that the optimal procedure is easilly trapped into local minimum value and the speed of convergence is very slow.A kind of improvement BP neurel network algorithm is proposed in the paper.The classical non-linear functions is improved by introducing a parameter，after that the improved algorithm is applied into the practical teaching evaluation；Carrided on the comparison with the other values，it indicates that the improved algorithm has the very good effect in the aspects of the speed of convergence and error evaluation.In the end，the logical evaluated teaching effect is reasonably proved by the selecting appropriate value of the parameter based on the results analysis of the real data.