Abstract: In the view of the whole growth season(from April 30,1999 to September 30,1999),the whole sunshine radiant energy reaching Carex lasiocarpa wetland ecosystem is about 2 673 06 MJ/m² .The accumulation of the whole sunshine radiant energy presents singlet type(parabola type)in different time in a day;the overall spectroradiation also presents obvious singlet type(parabola type) in different time in a day;and in parts of the spectroradiation,the distribution coefficient of photosynthesis availability radiation(PAR) is always biggest,with net infrared radiation(NIR) in the next place and ultraviolet radiation(UR) the smallest.The net radiation is correlative to the vegetation seasonal phase in this zone,which is bigger in the initial stage and the last stage and smaller in the flush stage.