In order to reveal the effect of sucrose on the response to phosphorus starvation stress and sucrose metabolism of Chinese fir under low phosphorus stress, two Chinese fir (Cunninghamialanceolata) genotypes M32 and M28 with different phosphorus efficiency were selected for the sucrose addition experiment under low phosphorus stress, and theeffects of sucrose addition on morphological and physiological characteristics of the Chinese fir under low phosphorus stress and gene expression related to low phosphorus induction were analyzed.The results showed that the addition of sucrose promoted the increase of Chinese fir seedling height, root length, root surface area, average root diameter, root volume, root and leaf tissue sucrose content, and root and leaf tissue inorganic phosphorus content under low phosphorus stress, but it was still significantly lower than the normal phosphorus supply. Phosphorus starvation promoted the accumulation of anthocyanin in Chinese fir leaves, while the addition of sucrose under normal phosphorus supply and low phosphorus stress significantly promoted the increase of anthocyanin content in leaves. With the prolongation of stress time, the sucrose content in root and leaf tissue of M28 and M32 are significantly different, and the sucrose synthase activity and sucrose phosphate synthase activity in root and leaf tissue of M28 are higher than those of M32. The expression of sucrose synthase ClSuSy in the root of M28 and M32 was down-regulated by low phosphorus stress, but the addition of sucrose significantly increased the expression of ClSuSy. The expression of ClSuSy of M28 under the treatment of normal phosphorus supply and addition of sucrose was significantly higher than that of other treatments. Sucrose transporter SUT4, phosphorus transporter ClPht1; 4, purple acid phosphatase PAP1 and PAP11 were generally up-regulated by low phosphorus stress in roots of M28 and M32, and down-regulated by sucrose addition treatment. Under phosphorus starvationstress, the expression level of SUT4 in M32 roots treated with or without sucrose increased significantly at 15 days, and fell to normal levels at 45 days. The expression levels of ClPht1;4 and PAP1 under low phosphorus stress at 15 days were significantly higher than those at 45 days, and the expression of ClPht1;4 in roots of M32 was much higher than that of M28. This study shows that sucrose has an important effect on the response of Chinese fir to low phosphorus stress and sucrose metabolism. The addition of sucrose treatment under low phosphorus stress can alleviate the response of Chinese fir to low phosphorus stress to a certain extent.