In order to explore the effects of amino acids.chelated.calcium on yield，quality and nutrient absorption of lettuce and to determine the optimal dosage，a field experiment was carried out with different concentrations (0.05%，0.1%，0.3%，0.5% and 1%)，and spraying water was used as control.The results showed that spraying amino acids chelated calcium increased the yield of lettuce，and the yield of 0.5% concentration was the highest，which was 16.27% higher than that of the control treatment.Both 0.3% and 0.5% concentrations treatments increased the content of vitamin C and decreased the content of nitrate.Amino acids chelated calcium significantly increased the total calcium content of lettuce by 9.73%～40.02%，compared with the control treatment.0.3% and 0.5% concentrations treatments increased the absorption of phosphorus and potassium.The concentration of 0.5% treatment had the highest economic benefit and production to investment ratio，and significantly increased farmers’ income.By comprehensive comparison，the optimal concentration of amino acids chelated calcium is 0.3%～0.5%，and the benefit is significant.