The study is being conducted to evaluate the efficacy, and safety of SHR-1918 in reducing serum low-density lipoprotein cholesterol (LDL-C) and total triglycerides (TG) in patients with hyperlipidemia compared with placebo, and also includes To evaluate the effectiveness of SHR-1918 in reducing other lipid indicators in patients with mixed hyperlipidemia and to assess the safety of SHR-1918 in patients with mixed hyperlipidemia.

Inclusion Criteria:

1. the age must be at least 18 years old, and both men and women are eligible;
2. the patient was receiving a stable dose of statins at the time of screening,, and the fasting LDL-C met: For individuals with extremely high risk of ASCVD, LDL-C≥1.4 mmol/L; for those with very high risk of ASCVD, LDL-C≥1.8 mmol/L; and for those with medium and high risk of ASCVD, ≥2.6 mol/L;
3. Fasting TG≥ 1.7 mmol/L;
4. Understand the research procedures and methods, voluntarily participate in this trial and sign the informed consent form in person；

Exclusion Criteria:

1. poorly controlled hypertension (systolic blood pressure ≥160 mmHg and/or diastolic blood pressure ≥100 mmHg) at the time of screening or before randomization；
2. Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) or γ -glutamyl transferase (GGT) > 3× upper limit of normal (ULN), or total bilirubin > 2×ULN；
3. Thyroid stimulating hormone (TSH) is lower than the lower limit of normal (LLN) or greater than 1.5×ULN；
4. The estimated glomerular filtration rate (eGFR) is less than 30 mL/min/1.73m2；
5. Previously suffering from diseases that have a significant impact on blood lipid levels, such as nephrotic syndrome, severe liver diseases, Cushing's syndrome, etc