To explore the controlling effect of different dosages of gibberellin(GA3) contained in the foliar fertilizer mingled by potassium dihydrogen phosphate and gibberellin(GA3) and the spraying times of gibberellin(GA3) at heading stage on the resistance of rice to low temperature stress during the flowering period,two rice cultivars matured lately and sensitive to low-temperature stress at heading stage,hybrid ‘Peiliangyou 537’ and conventional ‘Ezhong 5’,were used as experimental materials in this study.Twenty four adjustment patterns including the supplement of 0.0（A0），7.5(A1)，15.0（A2），22.5(A3)，30.0(A4)，37.5 g(A5) of GA3 based on 3.0 g/hm2 potassium dihydrogen phosphate and the spraying time at spike initial appearance stage (B1),initial heading stage (B2),heading stage (B3),full heading stage (B4) were adopted,thereafter heading dynamics,uniformity of panicle layer,yield and yield components of rice were investigated.The results showed that the 1 000-grains weight,grains per panicle,rate of seed setting,heading time and yield of rice under the patterns with spraying dosage of GA3 at 15.0-22.5 g/hm2 and the spraying time at B1 or B2 were better than those under other patterns and spraying times.However,under spraying the foliar fertilizer at B3 or B4,high rice yield requires the increase of spraying dosage.Increasing of spraying dosage or earlier spray time during heading period could improve the uniformity of rice panicle layer,but the former would diminish grain-filling and decrease 1000-grain weight.The addition of GA3 in the fertilizer can increase the resistance of rice to low temperature,in which the appropriate dosage of GA3 is 15.0-22.5 g/hm2.The increased dosage of GA3 may be useful to improve rice yield when the foliar fertilizer spraying time is delayed due to rain.