Taking a 7-year-old wine grape “Cabernet Sauvignon” as the research object，the effects of different magnesium application rates and methods on the photosynthetic characteristics，yield，quality and economic benefits of wine grapes on the basis of conventional fertilization were explored in this study. Five spraying + dripping magnesium fertilizer treatments (S1F1，S2F2，S3F3，S4F4，S5F5)and five dripping magnesium fertilizer treatments(S6F0，S7F0，S8F0，S9F0，S10F0)were set up. The results showed that both the dripping and spraying application methods of magnesium fertilizer on the leaf significantly increased leaf photosynthetic characteristics，improved grape berries morphology，fruit production，promoted berries titratable acid，tannins，anthocyanins and total phenol accumulation，and improved the quality of fruits. Among them，the yield of the treatments of foliar spraying with a concentration of 0.135%+ dripping 161.8 kg/hm² magnesium fertilizer and dripping 323.7 kg/hm² magnesium fertilizer increased by 23.8% and 22.0%，and the economic benefits increased by 36.1% and 32.8%，respectively，compared with non-magnesium treatment S0F0. The S3F3 had the highest economic benefit，the highest yield to investment ratio and the higher fertilizer utilization rate，which is the best magnesium application measure under the soil condition.