LDL cholesterol of 4mmol/L is borderline elevated and not considered serious, but if combined with coronary heart disease and hypertension, it should be treated with active intervention. LDL cholesterol is a cholesterol-rich lipoprotein. Elevated LDL can contribute to the formation of atherosclerotic plaque, which is an important risk factor for atherosclerotic cardiovascular disease. The ideal level of LDL cholesterol is <2.6 mmol/L, and the appropriate level is <3.4 mmol/L. When LDL cholesterol is ≥3.4 mmol/L but <4.1 mmol/L, it is a borderline elevated level, and when it is ≥4.1 mmol/L, it is an elevated level. Elevated LDL cholesterol is mostly associated with familial hypercholesterolemia, mixed hyperlipoproteinemia, diabetes mellitus, hypothyroidism, nephrotic syndrome obesity, and diabetes mellitus. In conclusion, LDL cholesterol of 4mmol/L is borderline elevated, but it is very close to being elevated, so patients should actively intervene with diet and exercise, control the fat and cholesterol intake in the diet, eat a light diet, and eat more vegetables. Daily exercise should be strengthened and weight should be reasonably controlled. If the examination finds that LDL cholesterol is abnormally elevated, it is necessary to go to the cardiovascular department of the hospital in a timely manner, and follow the doctor's advice to take medication actively.