Organic-inorganic hybrid perovskites based on methylammonium lead halide are being widely studied nowadays as it has a variety of interesting optical,magnetic and electronic application in the perovskite solar cells field[1-3].In this work,the electronic band structure,and absorption spectrum of CH3NH3PbI(3-x)Clx(x=0,1,2,3)hybrid perovskite structures were calculated by the first principles calculation.The results confirmed that the computed band gaps are direct and adjustable,ranging from 1.572 to 2.375 eV(Figure 1),when x going from 0 to 3 for CH3NH3PbI(3-x)Clx perovskite.All of them are closely to the experimental values[4].Moreover,CH3NH3PbI3 exhibit strong photon absorption in the wavelength span from 200 to 800 nm,indicated this material was a good light-absorber over the whole visible solar emission spectrum.