Urine protein 3 + suggests that urine protein positive, may be strenuous exercise and other physiological reasons, may also be glomerular filtration membrane permeability changes, tubular reabsorption obstacles and other pathological reasons. 1. Physiological reasons: physiological proteinuria is more common in the case of strenuous exercise, fever, etc., the patient’s kidneys have no organic lesions, no special treatment, after resting, the urine protein can usually turn negative. 2. Pathologic causes: (1) Glomerular filtration membrane permeability change: glomerulonephritis can cause the integrity of glomerular filtration membrane to be destroyed and permeability to be reduced, proteinuria occurs, resulting in urinary protein 3+. (2) renal tubular reabsorption disorder: renal tubular lesions, resulting in reduced reabsorption, can not absorb the glomerular filtration of protein, resulting in protein excreted in the urine, will also appear urine protein 3 +. Urine protein 3+ may also have other causes, if the patient found urine protein positive, it is recommended to go to the regular hospital in time to improve the examination to clarify the cause of the disease, under the guidance of the doctor to the targeted treatment or treatment.