In order to expand the application field of struvite(MAP) pellet crystallization technology, the optimal conditions for struvite pellet formation at low phosphorus concentrations were investigated. Results show that the phosphorus concentration over 50mg/L would be better for application of this technology. The optimal conditions for struvite pellet formation were as follows:pH=9.0 and phosphorus to nitrogen molar ratio=1:8. Under the conditions, the average size of harvested struvite particle reached 0.56mm, the volume growth rate was 4.95cm³/h and the struvite purity reached 99.9%. In order to further optimize MAP formation in the fluidized bed reactor, CFD software(Fluent 6.3) was used to simulate the flow fed to the reactor. It turned out that the bottom-up hydraulic classification was formed obviously in the growing zone of the crystallizer. Velocity in the cross-section was relatively uniform, which is beneficial to struvite formation. But some adverse conditions such as dead zone, vortexes and circulation loops were also present in the settling and influent zones. Therefore, it is necessary to improve the connection between the growing zone and settling zone as well as the distribution of inlet pipes to obtain high-quality MAP pellets.