A negative urine protein test with three plus signs means that the patient has proteinuria, a negative value is a reference value, that is, a negative result under normal conditions, but the patient’s actual test is only three plus signs, that is, there are abnormalities. There are various causes of nephropathy, such as glomerulonephritis, nephrotic syndrome, etc. Patients need to go to the nephrology department for further examination, and also need to do 24h urine protein quantification test to assess the condition, the most causes of increased urine protein, there may be immunogenic factors, there may also be complement system diseases, these are required to carry out relevant tests to further confirm the diagnosis. Surgical diseases can also lead to proteinuria with three plus signs, often seen in severe infections or the presence of post-renal obstruction, resulting in acute renal failure, which may also lead to urine protein with three plus signs. It is recommended that patients go to the hospital for detailed examination and evaluation to clarify the specific causes and give symptomatic drug treatment to restore health status early.