Coupled the photosynthesis with transpiration and adjustment of stoma,a dynamic ecological model for simulating the canopy photosynthesis of winter wheat was established by scaling up from the biochemical scale to canopy scale,in which the effects of O_3,CO_2 and solar spectrum on crop photosynthesis were fully considered.Validation of the model against the data measured with CI-301PS portable photosynthesis analyzer showed that the leaf photosynthesis model passed the correlation significance test and had a fairly high accuracy.Numerical analysis showed that the canopy photosynthesis rate would be reduced by 29% if the O_3 concentration increases from 0 ppbv to 200 ppbv,whereas the canopy photosynthesis rate would increase by about 37% while the CO_2 concentration increases from 330 ppmv to 660 ppmv,and the canopy photosynthesis rate would be reduced by 27%0 or so under the condition that the spectrum coefficient changed from 0.5 to 0.4.If the O_3 concentration reached 200 ppbv at noon on the typical sunny day with higher radiation,the canopy photosynthesis will be reduced slightly in the suburb area where the pollution is serious and the photochemical fog is easy to be formed,contrast with that in the clear region and regardless of the climate change,due to the fact that the positive effect of CO_2 on crop photosynthesis can not compensate the negative effect of O_3 on crop photosynthesis.The canopy photosynthesis will be reduced by 35% or so than the BASE value at present,when the spectrum of photosynthetic active radiation (PAR) reduces to 0.4 or so. Coupled the photosynthesis with transpiration and adjustment of stoma, a dynamic ecological model for simulating the canopy photosynthesis of winter wheat was established by scaling up from the biochemical scale to canopy scale, in which the effects of O_3, CO_2 and solar spectrum on crop photosynthesis fully considered. Control of the model against the data with CI-301PS portable photosynthesis analyzer showed that the leaf photosynthesis model passed the correlation significance test and had a fairly high accuracy. Numerical analysis showed that the canopy photosynthesis rate would be reduced by 29% if the O_3 concentration increases from 0 ppbv to 200 ppbv, and the canopy photosynthesis rate would increase by about 37% while the CO_2 concentration increases from 330 ppmv to 660 ppmv, and the canopy photosynthesis rate would be reduced by 27% 0 or so under the condition that the spectrum coefficient changed from 0.5 to 0.4. If the O_3 concentration reached 200 ppbv at noo n on the typical sunny day with higher radiation, the canopy photosynthesis will be reduced slightly in the suburb area where the pollution is serious and the photochemical fog is easy to be formed, contrast with that in the clear region and regardless of the climate change, due to the fact that the positive effect of CO_2 on crop photosynthesis can not compensate the negative effect of O_3 on crop photosynthesis. The canopy photosynthesis will be reduced by 35% or so than the BASE value at present, when the spectrum of photosynthetic active radiation (PAR) reduces to 0.4 or so.