The energy transfer from Tb3+ to Eu3+-doped SiO2 (SiO2: Eu3+, Tb3+) inverse opal photonic crystals was investigated by photoluminescence and fluorescence lifetime. The results showed that the photonic band gap enhanced energy transfer from the donor Tb3+ to the acceptor Eu3+. When the fluorescence emission wavelength of Tb3+ overlaps the photonic band gap, the fluorescence intensity of Tb3+ is suppressed, and the fluorescence intensity of Eu3+ is increased because of the enhancement of energy transfer. In addition, the fluorescence lifetime of Tb3+ decreased.