Abstract: A saturated-unsaturated numerical model of seepage flow with free surface is established. Water head and saturation are variables in this model. The rationality and accuracy are proved by the comparisons of 2D and 3D results. By analyzing the correlation of data, the connatural characteristics of the algorithm and the distribution of time consumed by the Finite Element Method, the serial program is transformed into a parallel program with OpenMP Application Programming Interface. The parallel speedups of different scales are set out. The results show that this parallel model can get better linear speedup, which was related to the processor number and the simulation scale.