Abstract:[Objective] Mendelian randomization (MR) method was used to investigate the causal relationship between overweight and hip osteoarthritis, in order to provide theoretical basis for clinical prevention and treatment. [Methods] Using publicly available data from the Genome-wide association study (GWAS), overweight as an exposure factor and hip osteoarthritis as an outcome factor, instrumental variable (IV) related to overweight was extracted. The MR method based on inverse-variance weighted (IVW) method was the main research method. In additon, the MR-Egger method, weighted median (WME) method and weighted mode (WM) method and simple mode method (SM) was used to verify the results. Furthermore, the results were tested for heterogeneity, sensitivity and pleiotropy. [Results] IVW results showed that overweight was positively correlated with hip osteoarthritis (OR=1.720, 95% CI 1.320~2.250; P=6.23942E-05, <0.01). The result of MR-Egger analysis suggested that there was no pleiotropy in this study (P=0.503). The results of Cochran's Q test (P=0.540) suggested that there is no heterogeneity in the results of this study. The single nucleotide polymorphisms (SNPS) used for MR Analysis were removed successively, which indicated that a single SNP could not significantly affect the overall effectiveness, indicating that results of this study were stable and reliable. [Conclusion] There is a causal relationship between overweight and hip osteoarthritis.