In this paper, the effects of mercury vapor pressure on the surface morphology, dislocation density, crystal quality and electrical properties of CdTe materials are investigated by varying the amount of mercury used for annealing of CdTe materials. It is found that after annealing at three times the normal mercury amount, the surface morphology is flat, the roughness (Ra) reaches 0.235 nm, and the crystal mass decreases to a minimum of 44.7 arcsec dislocation density to 7.1×10⁴ cm². The Hall test results show that the material has been completely transformed to N-type.