Urine yellow urine smell bad may be urine concentration, diet and drug factors, urinary tract infections, diabetes and other factors. 1. Concentration of urine: drinking too little water for a long time or holding urine for a long time, resulting in urine concentration, the water in the urine is reduced, the content of other substances is too high, which will lead to yellow urine smell, urine will also show turbid state, drink more water, more urination, can be improved on their own. 2. Dietary factors: consume a lot of carrots or oral vitamin B, will lead to yellow urine, and some odor, belonging to physiological factors, adjust the diet and stop using medication can be restored on their own. 3. Urinary tract infections: such as cystitis, pyelonephritis, etc., the presence of excessive purulent substances and white blood cells in the urine can lead to yellow urine and a distinct odor, accompanied by pain in urination, urinary frequency, urinary urgency, fatigue, fever and other symptoms. 4. diabetes: diabetes, blood sugar continues to increase, may lead to ketoacidosis, will lead to yellow urine odor, usually rotten apple flavor, accompanied by fatigue, drinking and other symptoms. Urine yellow urine odor, and accompanied by other obvious urinary discomfort, it is recommended to consult a doctor for examination, clear whether there are disease factors, timely treatment under the guidance of the doctor.