Cd0.9Zn0.1Te wafers grown by vertical Bridgman method were annealed in cadmium vapor at different temperatures. The formerly established model correlating resistivity and conduction type of CdZnTe with the main diffusion parameter-diffusion coefficient is used in combination with the analysis of our experimental data (DCd=1.464×10-10, 1.085×10-11 and 4.167×10-13cm2/s), and the values of Cd self-diffusion coefficient in Cd0.9Zn0.1Te at 1073K, 973K and 873K have been obtained, which coincide closely with the Cd self-diffusion coefficient in CdTe provided by different authors. With the data, the effect of annealing time on the resistivity and change of conduction type of Cd0.9Zn0.1 Te wafers annealed in saturated Cd vapor at 1073K, 973K and 873K were simulated, and good agreement was found.