In order to improve the performances of CdZnTe 7-ray detector, it is key issue to get the crystal with high quality. Equilibrium partial pressures, pCd and pZn, over Cd1-xZnx melt were estimated based on thermodynamic relationship and then Cd0.9Zn0.1Te wafers were annealed under controlled Cd/Zn partial pressures provided by Cd1-xZnx alloy reservoir. The experimental results show that when CdZnTe wafers are annealed under the equilibrium partial pressures provided by Cd0.99Zn0.01 alloy reservoir for 5 days or more at 1073 K, the resistivity of the wafer can be raised by 6 times and IR transmittance raised by 10% or more, the size and density of Te precipitates are greatly reduced. Moreover, losing of Zn from the surface can be avoided, which Ieads to improvement of the Zn radial distribution. In addition, the relationship between the electrical performances of the wafers and different controlled pressures is also discussed. In order to improve the performances of CdZnTe 7-ray detector, it is key issue to get the crystal with high quality. Equilibrium partial pressures, pCd and pZn, over Cd1-xZnx melt were estimated based on thermodynamic relationship and then Cd0.9Zn0. 1Te wafers were annealed under controlled Cd / Zn partial pressures provided by Cd1-xZnx alloy reservoir. The experimental results show when when CdZnTe wafers are annealed under the equilibrium partial pressures provided by Cd0.99Zn0.01 alloy reservoir for 5 days or more at 1073 K, the resistivity of the wafer can be raised by 6 times and IR transmittance raised by 10% or more, the size and density of Te precipitates are greatly reduced. Furthermore, losing of Zn from the surface can be avoided, which Ieads to improvement of the Zn radial distribution. In addition, the relationship between the electrical performances of the wafers and different controversies is also discussed.