The I-V characteristics of the long-wavelength infrared HgCdTe photovoltaic devices fabricated by different process including standard process,reflowing process and post implantation annealing process were measured and investigated by model fitting analysis. This model includes four current components,such as diffusion current,generation-recombination current,band-to-band tunneling current and trap-assistant tunneling current. From the model fitting analysis,the trap concentration increased dominantly during the reflowing process,which led the the trap-assistant tunneling current and the g-r current increased largely. The reverse bias resistance dropped a lot and the performance of the device degraded. Compared to the performance of the post-implantation annealed device,it is presumed that the reason which led to the degradation of the performance of the reflowed device is the instability of the ZnS passivation layer.