Objective:To investigate the effects of PRR11 on lipase H, immunomodulator and Survivin levels in thyroid cancer cells.Methods:A retrospective analysis was performed on 30 patients (13 males and 17 females) who received surgery for thyroid cancer in the Department of Thyroid Surgery of Yantai Yantaishan Hospital from Jun. 2020 to Oct. 2022. According to the study protocol, normal thyroid epithelial cells were used as the control group, and SW579 thyroid cancer cells were divided into no-load group, PRR11 up-regulated group and PRR11 down-regulated group. SW579 cell proliferation was detected by MTT assay and the levels of TNF- a, IL-1 β and IL-6 were detected by enzym-linked immunosorbent assay (ELISA). Apoptosis of SW579 cells and expressions of CD4+CD25+ and CD8+CD28- were detected by flow cytometry, and Survivin protein expression was detected by western blot analysis. Results:The mrna expression level of PRR11in thyroid carcinoma tissues (1.54±0.34) was significantly higher than that in para-carcinoma tissues (1.02±0.54) and normal thyroid epithelial cell line NTHY-ORI 3-1 (1.02±0.65) ( P<0.05). The mRNA expression level of PRR11 in SW579 (2.54±0.87) was higher than that in K1 CELL (1.74±0.45) and IHH-4 CELL (1.86±0.55) ( P<0.05), so SW579 was selected as the experimental cell. The expressions of SW579 cell proliferation, apoptosis, LIPH, TNF-α, IL-1β, IL-6, CD4+CD25+, CD8+CD28- and Survivin were significantly lower than those of no-load group ( P> 0.05), but higher than those of no-load group ( P<0.05). SW579 cell apoptosis rate, CD4+CD25+, CD8+CD28- ratio decreased ( P<0.05). The proliferation rate, LIPH (6.45±1.34), TNF-α (1.85±0.36), IL-1β (96.47±6.44), IL-6 (1.43±0.86) and Survivin protein expression of SW579 cells in PRR11 down-regulated group were lower than those in control group and no-load group ( P<0.05). The apoptosis rate, CD4+CD25+ and CD8+CD28- of SW579 cells were higher than those of control group and no-load group ( P<0.05) . Conclusion:Down-regulation of PRR11 can reduce the expression of LIPH, regulate the level of immunomodulator and Survivin, enhance the body's immunity, inhibit the proliferation and promote the apoptosis of thyroid cancer cells, and provide a new strategy for the diagnosis, treatment and prognosis of thyroid cancer.