Abstract: ‘Lyuya’lettuce was used as the test material,and the calcium chloride solution was sprayed on the leaves.Five concentrations of calcium chloride solution were set up,0%（CK）,0.3%（T1）,0.5%（T2）,0.7%（T3）,0.9%（T4）.The effects of different concentrations on the quality of lettuce and dry heartburn were studied,in order to provide reference for improving the serious situation of dry and heart-burning of lettuce in plant factories and improving the yield and quality of lettuce.The results showed that the quality of lettuce sprayed with 0.5% calcium chloride was significantly improved compared with CK,and the protein content and soluble sugar content were the highest in all treatments.Calcium chloride had obvious effects on improving the dry heart rate of lettuce,and the dry heart rate decreased with the increase of concentration,but the yield and some quality decreased when the concentration exceeded 0.5%.Comprehensively,the spraying concentration of calcium chloride solution was 0.5%,which improved the quality of lettuce and significantly improved the dry heart condition of endogenous vegetables in plant factories.