Normal people should be negative for urine protein in urine routine, if there is urine protein (+), the following conditions should be considered: Firstly, we should exclude pseudo elevated urine protein caused by test errors or less concentrated urine from drinking water. Secondly, we need to exclude transient physiological proteinuria caused by fever, cold, strenuous exercise, cold, etc. After ruling out the above two two situations, pathological proteinuria needs to be considered, and the following causes are common: First, urinary tract infection, acute and chronic nephritis, prostatitis and other causes of urinary protein. Second, body wasting and Nutcracker syndrome can also lead to urinary protein. To identify what causes urine protein, 24h urine protein quantification, urine protein profile, kidney function and other related tests are needed, and if necessary, a kidney puncture biopsy is required to identify.