Abstract: [Objective]To evaluate the value of NONFH in the early diagnosis of femoral head necrosis by detecting the difference of retinol binding protein-4 (RBP4) between nontraumatic necrosis of femoral head (NONFH) and healthy people.[Methods] 70 patients with femoral head necrosis hospitalized in Linyi people's Hospital from August 2021 to December 2021 were selected as the NONFH group, and 62 healthy people in the physical examination center of our hospital at the same time were randomly selected as the control group. The serum RBP4 levels of the two groups were detected by enzyme-linked immunosorbent assay. Compare the general data between the two groups, and analyze the ROC curve of RBP4 in NONFH group and control group. [Results] The concentration of serum RBP4 protein in NONFH group was significantly lower than that in normalgroup (P<0.05). There was no significant difference in the concentration of serum RBP4 protein in patients with different causes and hips (P>0.05); The concentration of serum RBP4 protein after collapse was lower than that before collapse (P<0.05), and the level of RBP4 in patients with bilateral necrosis was significantly lower than that in patients with unilateral necrosis (P<0.05); There was significant difference in the concentration of serum RBP4 protein between patients with Arco stage Ⅱ, Ⅲ and Ⅳ (P<0.05); There was a negative correlation between serum protein P4 concentration and serum protein P4.0. ROC curve showed that serum RBP4 level had certain sensitivity (64.29%) and specificity (96.77%) in the diagnosis of femoral head necrosis and collapse. [Conclusion] The level of serum RBP4 may reflect the disease severity of NONFH. It is a potential serum marker for the diagnosis of NONFH and has certain clinical guiding significance.