Improving plant structure is pivotal for increasing the potential yield of crops. The aim of this paper was to evaluate the influence of leaf angle and leaf area index (LAI) on light interception efficiency and capacity of biomass production of rice using 3-D models. A group of virtual plant types of rice, with different combinations of leaf angles, was designed based on the 3-D data of a real rice canopy which was digitized in situ in the field at the filling stage. The results indicated that plant types with excessively steep leaves could lead a significant decrease of photosynthesis at higher solar inclination angle. An optimum LAI corresponding to the peak photosynthetic rate can be found for each of the plant type. To overcome the obstacle of heavy computing in this study, computer cluster and message passing interface were used to provide an efficient and economical way for simulating the 3-D light distribution and photosynthetic rate in rice canopies.