Atmospheric pressure metal-organic chemical-vapour deposition (MOCVD) has been used to infiltrate the voids within synthetic opals with InP to modify the natural photonic behaviour of these materials. Experiment is carried out for given growth conditions to study the effect of growth cycles. Morphologies and reflectivity spectrum properties of the artificial opal and InP-infiltrated artificial opal were researched by SEM and UV-Vis spectrometer. The results show that an increase in the InP infiltrationl of the pore volume is achieved if the total time of each reactant over the opal is constant while the total number of cycles is increased. The extent of InP infill within the voids increasing in turn increases the extent of refractive index contrast between the silica spheres and the void, and it is possible to modify the opal photonic band gap in a controllable manner. It is also found that the periodic growth is in favor of InP infiltration the InP grown shows a high quality by SEM. The study provides a scientific basis for manufacturing three-dimensional InP photonic crystals.