Abstract: In order to improve the photosynthetic productivity of crops,an experimental site was set to observe solar radiation and photosynthetic production of crops in Longhai,Fujian from 2006 to 2009.The results showed that(1) based on solar radiation and sunshine rate,an empirical formula for calculating the monthly,seasonal radiation in Longhai was established;(2) a positive correlation between solar radiation and plant’s dry matter accumulation and economic yield was found-the solar radiation during the period between rice full heading and maturation had a significant and determining effect on the grain yield;(3) the average light energy utilization(Eu) rates were 2.10%,1.98% and 1.85%,respectively,in the entire growth period of Longhai early rice,the late rice and the potatoes,and in the short-term the highest Eu was 4.26%;and(4) estimated by the local annual solar radiation and the maximum Eu value,the greatest theoretical yields of the early rice,the late rice and the potatoes could be 1.6 to1.8 times higher than the current production of the three crops indicating a substantial production increase potential.By more efficient utilization of the solar energy,increase in crop yield could be realized.