A neatly controllable photonic band gap formed in a four-level tripod system in the solid material,Pr3+-doped yttrium orthosilicate (Pr∶YSO) is investigated.Driven by two standing waves,the sample is just like a photonic crystal to the weak probe.Based on the numerical simulation and the analytic result we present a clear and full-scale view on the induced band gap in the inhomogeneously broadened tripod system.