Abstract: Digital plant canopy imager and photosynthesis analyzer system were used to analyze characteristics of canopy structure, photosynthetic physiology and micro-environmental factors at R4-R5 stage in different yielding soybean cultivars or lines with different maturities. The results showed that the common traits of high yielding soybean were high in LAI, uniform in foliar distribution in all horizontal directions, less variance of photosynthetic rate between top and bottom leaves in canopy and relatively high photosynthetic rate of the whole canopy to enhance photosynthetic productivity. Thus, pod number, seed number and seed weight per plant，especially pod and seed number in top and medium canopy increased. The characters of high yielding colony in different maturing cultivars were different. Light interception was more important for early cultivars. Less foliage inclination angle would be benefit to intercept more solar energy during yielding period; but for late soybean cultivars, the colony was more closure and LAI was higher, so big foliage inclination angle in all layers of high yielding colony made more solar radiation penetrate into the inner canopy, which would be good for yield formation

Key words: Soybean, Canopy, Ecological physiology, Yield