In the field of plant lighting, since the illuminated surface of the cultivation system changes continuously with the growth of the plant, the design of the plant lighting system need to consider the lighting situation and effect in the whole growth cycle and the space occupied by the plant growth process, so that it can provide the high illumination uniformity of the whole growth space. However, the extensive traditional plant lighting solutions are only optimized for a specific reference plane, which can not achieve the effect of high spatial illumination uniformity. Focusing on this issue, the lighting space of the whole plant culturist was taken as the research object, based on the theory of space lighting, and the recently proposed inverted light source and the traditional top array light source design scheme were taken as references to propose a dual light source module LED plant lighting system. The light source was set on both sides of the top and the bottom, and the high spatial uniformity were achieved through the complementary mixing of the two parts of light source. Taguchi method was used to simplify the experimental process, the variation analysis was used to optimize the key structural parameters, and the influence of light source distribution curve on the performance of plant lighting system was further studied. After several times of optimization, the optimal design of illumination uniformity of horizontal and vertical surfaces is 93.48% and 88.54% respectively, color-mixed uniformity is 90% and 87.13% respectively, and light energy utilization rate of planting surface is 41.63%.