Effects of Sulphate-potassium Magnesium fertilizer as base fertilizer on some physiological characters and yield of japonica rice was studied with Chujing 28 by using pot experiment.This experiment set up six treatments of two fertilizers（1g per pot and 2g per /pot）,separate application or whether the combination of farm manure,no fertilizer treatments and without applying any fertilizers as controls.The results showed that Sulphate-potassium Magnesium fertilizer was beneficial to increase the effective panicle number,grain number per spike,seed setting rate and grain yield.Sulphate-potassium Magnesium fertilizer combine farm manure can effectively increase the chlorophyll contents and reduced the descent speed of the chlorophyll contents in the late growth stage.Sulphate-Potassium Magnesium fertilizer was beneficial to enhance significantly the superoxide dismutase（SOD） activity and free Proline content after heading,but decreased slowly during the later filling stage.Thus enhanced osmotic adjustment ability,eliminated free radicals ability and resistanced delaying senescence.Therefore,it is recommended in the production that the fertilizer methods is best with farm manure1500 kg/667m2 and Sulphate-Potassium Magnesium fertilizer 20 kg/667m^2 as base fertilizer.