The effects of spraying calcium fertilizer on fruitquality，such as sugar and acid accumulation in grapefruit，were studied under field conditions，which provided theoretical basis for rational supplement of calcium fertilizer in grapeproduction.Two kinds of calcium fertilizer，calcium nitrate and calcium amino acid，were sprayed on grape panicleduring the period of fruit colorconversion.The concentration of calcium nitrate solution was0.3%，0.5%respectively，theconcentration of calcium amino acid solution was set to0.1%，0.08%respectively，and spraying fresh water was set as thecontrol.The effects of spraying calcium fertilizer on glucose and acid accumulation and other fruit quality werestudied.The results showed that exogenous application of 0.1% calcium amino acid solution promoted the accumulation of fructose andglucose and inhibited the degradation of tartaric acid and oxalic acid during fruitripening.Fruit firmness and soluble sugarcontent increased by 35.71% and 38.66%respectively，and titratable acid content decreased by 30.17% compared with thecontrol.Exogenous application of 0.5% calcium nitrate solution promoted the accumulation offructose，glucose andsucrose，promoted the degradation of tartaric acid and citric acid，increased the accumulation of oxalic acid during fruit ripening.The fruit firmness，soluble solids and soluble sugar content increased by 47.74%，7.99% and 43.34% respectively，andthe titratable acid content decreased by 28.89% compared with the control.Combined sugar and acid content and otherfruitquality，it was concluded that spraying 0.5% calcium nitrate solution had the better effect on improving the fruit quality during the color conversion period of 'Summer Black' grape.