Under normal circumstances, protein in urine routine should be negative, if it is weakly positive, we need to exclude physiological proteinuria, such as urine routine examination after having strenuous exercise, it may show weakly positive, it is recommended to review urine routine after rest, if it turns negative it is a kind of physiological proteinuria. If the proteinuria is caused by the kidney itself, such as chronic pyelonephritis, nephrotic syndrome, etc., we can make a comprehensive judgment by kidney ultrasound, kidney function, liver function, urine routine, 24hUP quantification, etc., and then guide the next step of treatment. There are also some systemic diseases that cause positive urine protein, such as myeloma, which causes monoclonal protein elevation causing overflow proteinuria, and this needs to be combined with other tests to make a comprehensive determination.