Using multi-photon nonlinear Compton scattering model and finite-difference time-domain method, the influences of the density and temperature characteristics of band gap for un-magnetized plasma photonic crystals produced by multi-photon nonlinear Compton scattering are studied. A new mechanism of the modulation on the photonic band gap formed by incident light, Compton scattered light and plasma density and temperature is given. The results show that the photonic band gap of plasma photonic crystals can be developed by using the change of the plasma density and temperature, but this developing effect can be decreased by Compton scattering. A larger shift to the high frequency direction of the photonic band gap than that before the Compton scattering can take place. Therefore, the high pass filter characteristic of the plasma photonic crystal can be better attained.