Non-alcoholic fatty liver disease (NAFLD) is strongly associated with dyslipidemia, and the non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio (NHHR) is a more comprehensive indicator of lipids. This study aimed to investigate the association between NHHR and hepatic steatosis and liver fibrosis. The 2017-2020 national health and nutrition examination survey (NHANES) dataset was used for the cross-sectional survey. NHHR was calculated by lipid profiling, and the controlled attenuation parameter (CAP) and liver stiffness measurement (LSM) were determined by vibration-controlled transient elastography (VCTE). Multiple linear regression models were used to test the linear association between NHHR and hepatic steatosis and liver fibrosis. Fitted smoothing curves and threshold effect analysis were used to describe the nonlinear relationships. This population-based study included 6575 adults (≥ 18 years). After adjusting for covariates, we found a U-shaped association between NHHR and hepatic steatosis, with a breakpoint of 1.26. There was a negative association on the left side of the breakpoint (OR [95% CI] - 24.31 [- 43.92, - 4.70]) and a positive association on the right side of the breakpoint (OR [95% CI] 3.82 [2.05, 5.59]). There was no significant association between NHHR and liver fibrosis. In addition, subgroup analyses and interaction tests showed stable results. In summary, NHHR has a U-shaped association with hepatic steatosis and no significant association with liver fibrosis. Keeping NHHR below 1.26 may be an effective option to reduce the risk of hepatic steatosis. NHHR is a more efficient and cost-effective marker for NAFLD surveillance that can be utilized in future clinical practice.