Abstract: Abstract: Grain productivity mainly depends on the radiation use efficiency (RUE) of crops. The RUE can be defined as the relationship between the accumulation of biomass related to the light intercepted by the crop. It is necessary to clarify the relationship between crop photosynthesis, light interception ability, and RUE, in order to improve the utilization efficiency of crop resource, further to adjust planting structure. Additionally, the Northeast China, as an important major grain producing area, is playing a critical role in national food security. Taking maize, spring wheat, soybean, millet, and potato in Lishu county of Jilin province in Northeast China as research materials, 2 a field experiments were conducted to investigate the photosynthetic characteristics, light interception, and RUE of five main crops in different growing periods. The crops were first planted in the traditional way, where the cultivation and management were commonly used in the local area. A LI-6400XT portable photosynthesis and fluorescence system was used to measure the diurnal changes of net photosynthetic rate in the vegetative and reproductive growth stages. The light response curve was fitted to obtain the main parameters of light response. A linear light quantum analyzer was selected to measure the light interception of different parts in the key growth period. The light interception and bioaccumulation were used to calculate the utilization efficiency of light energy in different growth periods, whereas, the photosynthetic ally active effective radiation and bioaccumulation were used to calculate that in the whole growing season. The results showed that the maximum net photosynthetic rates of maize and millet were higher than 28 μmol/(m2·s) at the vegetative and reproductive growth stages, indicating significantly higher than those of soybean, spring wheat, and potato. The diurnal variation curve of net photosynthetic rate for soybean and potato showed a single peak curve, where the peak appeared in the morning. Maize and millet showed a high light saturation point, and a low light compensation point of each crop leaf, where the suitable range of light intensity for photosynthesis was higher than that of other crops. Maize and millet also obviously dominated in the net photosynthetic rate curve and main light response parameters of various crops in the vegetative and reproductive growth stages. The light interception ability of maize, soybean and millet was significantly better than that of other crops, but the planting density can be appropriately reduced to avoid the influence on the development of middle and lower leaves of crops. Nevertheless, the increase of planting density can contribute to improve the light interception ability in the population of potato and wheat. In the transition period from vegetative to reproductive growth stage, the maximum light interception was found in the upper part of crops, indicating an important impact on the improvement of crops RUE. The RUE of potato, maize and millet in the whole growing season was significantly higher than that of wheat and soybean, whereas, that in the transition period from vegetative to reproductive growth was higher than that in other growth periods. Therefore, it is recommended that potato, maize, and millet can be planted preferentially on the adjustment of planting structure using RUE and yield. The finding can provide valuable information to formulate more reasonable and effective planting structure, according to resource utilization efficiency in the future.