Abstract: Using simulation test method,the energy conversion in a grassdyhe-fishpond ecosystem is studied, and with a productive system as control,the economic benefit of the ecosystem is analyzed.The results show ：1.the utilization rate of solar energy by grass is 0.6%,and the conversion efficiency from grass to fish is respectively 7.5% and 9.5% for tested and productive fishponds,2.farming fish with grass had a bet- ter benefit than to those of pig-raising and cropping.

Key words: cotton, super-high yielding, canopy structure, light distribution, photosynthesis, nonfoliar green organ.