The potential productivity of radiation,temperature and water of corn In Changchun District was calculated according to the model of Huang Bingwei,Jiang Aillang and the method of Yu luning as well as data of Changchun District.It was found that much potential productivity of radiation,temperature and water was not translated into real productivities yet,and the yield of corn wonld be increased largely if some on cultivation methods were taken to overcome the limiting of yield-reducing fuctors.The constraint factors of yield was analysed and the yield-increasing ways and the effective utililzation of radiation,temperature and water were discusssed finalls.