The main causes of high urine specific gravity are blood volume deficiency and increased solutes in the urine. Urine specific gravity measurement provides a rough indication of the concentrating and diluting function of the renal tubules. The test is indicated in persons with kidney disease, in persons who are dehydrated or overhydrated, and when abnormal excretion of substances is suspected. The specific gravity of urine is 1.015-1.025 in morning urine or under normal dietary conditions, and values outside this range suggest the presence of elevated specific gravity. 1. Blood volume insufficiency: such as high fever, profuse sweating, vomiting, diarrhea, massive blood loss, severe burns, drinking too little water and so on, resulting in blood volume insufficiency, urine concentration, resulting in decreased urine volume and increased urine specific gravity. It is common in prerenal oliguria. 2. Increased solutes in urine: such as sugar, protein and cells in urine, tubular and other pathological conditions, can be seen in diabetes mellitus, acute glomerulonephritis, nephrotic syndrome and other diseases; in addition to this, it will also be affected by age, diet and urine volume. If abnormal urine specific gravity is found, it is recommended that the patient go to the nephrology department of the hospital in time, under the guidance of the relevant professional doctors, improve the relevant examinations to clarify the diagnosis, and follow the doctor’s instructions to standardize the treatment.