Proteinuria refers to the presence of protein in the urine. A routine urine test will indicate positive urine protein, which is indicated by a “+” sign. Most of the mild urine protein is no symptoms, only the more serious urine protein will appear increased foam in the urine, double lower limbs, facial edema and other performance. The first thing you need to distinguish is whether it is physiological proteinuria or pathological proteinuria, because proteinuria can also occur after fever or strenuous exercise, which is a physiological proteinuria, usually without any symptoms, and will disappear after controlling the fever. If the urinary routine is repeatedly positive in the absence of fever and strenuous exercise, it should be considered pathological proteinuria. Most pathological proteinuria is caused by kidney disease, even if the pathological proteinuria is mild there are no symptoms, only when the proteinuria is more serious will the corresponding symptoms appear, such as more urine foam, and will not disappear for a long time; double lower limbs, face, eyelids edema and other symptoms. In summary, most of the physiological proteinuria and mild pathological urine protein do not have any symptoms, but only the more serious urine protein will show increased foam in the urine, double lower limbs, facial edema and other performance.