Density states properties of two-dimension square lattice photonic crystals with III-V AlP, AlAs, AlSb and GaP semiconductor material were calculated by plane wave expansion method (PWM). The results showed that they have wide photonic band gaps. The width of band gap increases gradually with the increasing of permittivity difference and gets the maximum value at f=0.2a in the normalized frequency. The data reveals among these photonic crystals, the one with AlSb has the widest band gap. All these results provide theoretic basis for the photonic crystal devices.