CsPbBr3 is a promising material for high-performance high-energy radiation detectors with high detection efficiency and good stability. In the ingredient stage of preparing the CsPbBr3 single crystal by the vertical Bridgman technique, the oxygen will adsorb on the surface of raw materials, and gather above the sealed crucible after melting, if the contact between the raw material and the oxygen cannot be effectively isolated, and results in a gradually darker color of the single crystal along the growth direction. The color change does not change the band gap of the CsPbBr3. The electrical performance test of the upper end section of CsPbBr3 single crystals reveals that the resistivity gradually decreases, and the trap density and carrier mobility gradually increases from the center to the outside of CsPbBr3 single crystals. But the responsiveness to X-rays is unchanged from the center to the outside of CsPbBr3 single crystals. This paper contributes to studies on the growth of high-quality CsPbBr3 single crystals.