With oilseed rape(Brassica napus) hybrid the ‘Qinyou No.7’ as material and plants of which after flowering were managed according treatments:shading leaf,shading silique and plucking leaf,such a field experiment was conducted to investigated photosynthesis characteristics and influence of the silique and leaf photosynthesis on seed yield,seed fatty acid content and seed fatty acid profile in this paper.The results showed that:(1)1000-seed weight,yield and fatty acid content of the seed declined by 54.7%,62.1% and 44.2%,respectively for the treatment shading silique,while contents of glucosinolate in the seed,as well as palmitic acid and octadecoic acid in fatty acid of the seed significantly increased and linolenic acid significantly decreased.(2)When leaves of the rape plant after flowering were shaded or plucked off,the seeds number per silique reduced by 11.7%,11.3%,and 1000-seed weight decreased by 22.5%,17.9%,respectively as so the seed yield per plant decreased by 35.3%,44.7%,while linolenic acid contents of seed fatty acid significantly increased and no notable influence on total contents of fatty acid in seed.(3)After flowering,green silique peel of the rape plant grew up to maximum area 1.54 double versus to area of green leaves,and solar radiation distribution a great quantity located in silique layer,where net photosynthetic rate.The transpiration rate of the silique were significantly high than that of the leaf,though contents of chlorophyll a,b and phytoxanthin in the silique were far lower.Actually the silique photosynthesis responding to photon flux density exhibited a higher light compensation point and higher light saturation point compared to the leaf.This infers that the silique is relatively endurable to stronger light radiation intensity in environment.Thus the study revealed that silique layer of oilseed rape accepted major light radiation during post-flowering stage and exhibited higher photosynthetic activity.The silique was main photosynthetic organ of rape plant and strongly influenced yield,fatty acid content as well as fatty acid profile of seed by photosynthesis.