In recent years, multicrystalline silicon(mc-Si) solar cells extrudes the single crystal silicon solar cells in the market share of silicon bulk solar cells unceasingly due to the advantage of relatively low-cast. However, the growth method of mc-Si ingots causes the grain boundaries, dislocations and even harmful metal impurities, which are higher than single crystal silicon. It is a reason that the conversion efficiency of mc-Si is unable to catch up that of the single crystal silicon solar cells. This study will discuss the effect of removal of harmful impurities such as Fe, Co and Ni, etc by adding phosphorous diffusion gettering(PDG) in mc-Si solar cell processes. We believe that the procedure can reduce the internal carrier recombination rate and increase the minority carrier lifetime, further improve the conversion efficiency of solar cells. In this experiment, the minority carrier lifetime measurement is performed using the microwave-reflection photo-conductance-decay (MRPCD) technique, which is capable of determining the lifetime of a silicon wafer. We also used the secondary ion mass spectrometry(SIMS) to observe the distribution of metal impurities near silicon surface after PDG. It shows an increasing in the minority carrier lifetime from 24.3us to 45.6us, and conversion efficiency was improved about 2% for PDG treatment.