The mixing-induced CP asymmetries in B-> K* gamma -> K_S pi^0 gamma and B-> K* gamma -> K_L pi^0 gamma are expected to be small within the standard model. So they are among the most promising decay modes to test the standard model. In this paper, we compute the mixing-induced CP asymmetries in these decay modes, within the framework of the standard model, using perturbative QCD, and our conclusion is S_{K_S pi^0 gamma}=-S_{K_L pi^0 gamma}=-(3.5pm 1.7)times 10^{-2}.