Proteinuria is caused by a variety of reasons, including physiological factors and pathological factors. Physiological factors are mainly seen in their own state and emotional factors, standing, etc. Pathological factors are mainly seen in renal diseases. 1. Physiological factors (1) own state and emotional factors: often occurs in young adults, can be seen in nervousness, severe cold or heat, long-distance marching, strong physical labor, congestive heart failure, eating a high protein diet, after the removal of the cause of proteinuria can generally disappear quickly. (2) Standing: no urinary protein in the urine in the early morning, proteinuria gradually appears after getting up and moving around, when standing, walking or strengthening the posture of spinal convexity for a long period of time, the content of urinary protein increases, and the content of urinary protein decreases or disappears after lying down and resting for one hour, which occurs in the youth or adults with long and thin body type. 2. Pathologic factors (1) Primary glomerular diseases: including nephritis, nephrotic syndrome, renal insufficiency and so on. (2) Secondary glomerular diseases: including lupus nephritis, purpuric nephritis, diabetic nephropathy, gouty nephropathy, hypertensive nephropathy and so on. (3) Other renal diseases: including tubulointerstitial nephropathy, hereditary nephropathy, basement membrane nephropathy and so on. (4) Diseases such as urinary stones and urinary tract infections can also cause positive urine protein. The causes of proteinuria are more, it is recommended that when patients have proteinuria, they should consult a regular hospital in a timely manner to identify the cause of the disease and carry out targeted treatment, so as not to delay the condition.