γ-ray and x-ray detectors made by Cd1-xZnxTe alloy can gain high energy resolution and detect efficiency at room temperature due to its high atomic number, large energy gap and high density, which were well-developed recently. By well controlled of Cadmium partial pressure and compensatory doping technique, Ф90 mm Cd1-xZnxTe alloy obtained successfully (ρ≥1011 Ω·cm) by an improved-Bridgman method. 3 mm × 3 mm × 3 mm CZT detector was made at Kunming Institute of Physics, which has energy resolution of 3.52% (FWHM) at room temperature when detect 59.54 KeV Am241 γ-ray source.