It is recommended that the bladder can be filled up by drinking more water and holding urine properly. The filling of the bladder is mainly dependent on the increase of urine in the bladder. The purpose of a full bladder is mainly to prepare for the following tests, such as urological ultrasound, CT bladder, etc. The main reason why the bladder should be filled up is that when the bladder is filled up, it is better able to distinguish from the surrounding organs and organs, and in ultrasound the fluid is among the better distinguished. In contrast to fluid, gas can have an impact on the diagnosis of ultrasound. If the bladder can be filled up, the ultrasound of the bladder will be clearer, and the CT of the bladder will also be clearer because of the filling of the bladder, so it is recommended to drink more water and hold urine properly to fill up the bladder.