Erectile dysfunction (ED) is closely related to coronary heart disease (CHD). Apolipoprotein (Apo) A1, Apo B, and Apo A/Apo B are known to be predictive factors for CHD. They are not yet a definite laboratory marker for the diagnosis of ED in cardiology. Therefore, we investigated the association between Apo A1, Apo B, and Apo A/Apo B, and ED. To investigate the association between Apo A, Apo B, and Apo A/Apo B and the severity of ED. A total of 152 ED patients and 39 healthy control participants underwent a fasting blood draw to test for Apo A, Apo B, and Apo A/Apo B and a detailed laboratory examination. The International Erectile Function Index (IIEF-5) was used to determine the severity of ED. Receiver operating characteristic (ROC) curve analysis was performed to identify the cutoff values for Apo A, Apo B, and Apo A/Apo B. Each questionnaire was completed before any diagnosis was made or treatment performed. Several lipid profile indicators (Apo A, Apo B, Apo A/Apo B, lipoprotein (a), free fatty acids, and total cholesterol) were studied, along with several questionnaires. In our study, the number of patients with no ED, mild ED, mild-to-moderate ED, and moderate-to-severe ED were 39 (20.4%), 58 (30.4%), 36 (18.8%), and 58 (30.4%), respectively. Apo A and Apo A/Apo B were significantly reduced in patients with more severe ED (P = .037 and P < .001, respectively), while Apo B was significantly increased in patients with more severe ED (P = .002). According to the ROC curve, Apo A/Apo B had a medium diagnostic value for risk of ED with an AUC of 0.743 (95% CI: 0.68-0.80). For moderate-to-severe ED, 3 apolipoprotein indexes, including Apo B, Apo A, and Apo A/Apo B had medium diagnostic performance with AUCs of 0.759 (95% CI: 0.66-0.84), 0.703 (95% CI: 0.60-0.79), and 0.808 (95% CI: 0.72-0.88), respectively. Our results can inform cardiologists in the assessment of ED in patients with CHD. This study is the first to investigate the association between apolipoprotein and ED in China. The major limitations are that our sample size was too small to have matched controls without ED for different Apo levels. Our results showed that Apo B, Apo A, and Apo A/Apo B can be used as markers to evaluate the risk of ED and that these proteins play an important role in the etiology of ED. Li X, Li D. The Suggestive Effect of Apo A, Apo B, and Apo A/Apo B on Erectile Dysfunction. J Sex Med 2021;18:448-456.