Perovskite CH3NH3PbI3 has been attracted significant attention because of its high absorption coefficient, the ideal band gap energy (Eg =1.5 eV) and the low cost of synthesis. However, CH3NH3PbI3 had an intrinsic issue regarding the long-term stability due to the unstable bond of Pb‒I. In addition, the CH3NH3PbI3 cubic structure had easily been occurred in the phase transition. The chloride or bromide ion, a high electronegativity, was used to exchange for I- in CH3NH3PbI3 to create the mixed halide perovskites, CH3NH3PbI3-xBrx (x = 0.5‒1.5) and CH3NH3PbI1,8Cl1,2. The structure of materials was identified by XRD. The stability of CH3NH3PbI3-xBrx or CH3NH3PbI3-xClx was investigated during 290 hours in an environmental chamber (80 % humidity, 40 °C). The band gap of perovskites could be tunned by controlling the Cl-, Br- or I- ratio. The result revealed that the half‒life of CH3NH3PbI3-xBrx and CH3NH3PbI3-xClx were higher from 2 to 4 times than that of CH3NH3PbI3. Perovskite solar cells based-on CH3NH3PbI2,5Br0,5 and CH3NH3PbI1,8Cl1,2 were fabricated by using spin-dip coating 2 steps process possessing the maximum efficiency of 11.4 % (Jsc = 0.99 mA.cm-2, Voc = 1.05 V) and 12.3 % (Jsc = 1.14 mA.cm-2, Voc = 1.01 V) under AM 1.5 simulated sunlight of 1,000 W.m-2 light intensity