The current voltage characteristics via temperature of midwavelength HgCdTe/Si photodiodes were measured and analyzed .The temperature range was from 30K to 240K, and the characteristic of R01000/T was measured and analyzed. The RV curve of 60K, 80K and 110K were modeled using different dark current mechanisms. The theoretical fitting of experimental data at 80K reveals the generationrecombination and trapassisted tunneling current dominates for zero and lowbias region. Reduction of generation recombination and trapassisted tunneling currents by selecting proper material and device technologies will improve our device performance.