Abstract: Objective To detect the changes of serum cartilage markers type Ⅰ collagen cross-linked C-terminal peptide (CTX-Ⅰ), type Ⅱ collagen carboxy-terminal peptide (CTX-Ⅱ), metalloproteinase 13 (MMP-13) and autophagy related genes Beclin-1 and LC3-Ⅱ in patients with osteoarthritis (KOA) and rheumatoid arthritis (RA), in order to explore its significance in the screening and diagnosis of KOA and RA.Methods Patients with KOA and RA who were admitted to Xuzhou First People's Hospital and Xuzhou Central Hospital from February 2022 to March 2023 were selected,including 57 KOA patients and 58 RA patients. Meanwhile, 50 healthy subjects over 60 years old and 60 healthy subjects under 35 years old who underwent health examination were also selected. The levels of serum cartilage markers CTX-1, CTX-2 and MMP-13 were detected by ELISA. The RNA levels of Beclin-1 and LC3-Ⅱ in peripheral blood among all groups were compared, and the diagnostic threshold was determined by plotting a receiver operating curve (ROC).Results The levels of serum CTX-Ⅰ, CTX-Ⅱ and MMP-13 in the KOA and RA groups were higher than those in the control group. The levels of serum CTX-Ⅱ in the RA group were higher than those in the KOA group (P<0.05), but there was no statistical difference in serum CTX-Ⅰ and MMP-13 levels between the two groups. The RNA levels of Beclin-1 and LC3-Ⅱ in the YC group were significantly higher than those in other groups (P<0.05 or <0.01). ROC curve analysis showed that serum CTX-Ⅰ, CTX-Ⅱ and MMP-13 showed diagnostic values for RA and KOA, and the area under ROC curve (AUC) were 0.789, 0.858, 0.619 and 0.769, 0.675, 0.748, respectively, and the AUC of combined diagnosis of multiple indicators were 0.876 and 0.814, respectively.Conclusions High levels of CTX-Ⅰ, CTX-Ⅱ and MMP-13 in serum and low levels of autophagy genes may be important factors leading to enhanced destructive activity in patients with KOA and RA, and can play a good role in diagnosis.