The invention relates to a disposable specimen taking-out device under a cystoscope, a ureteroscope and a nephroscope. The specimen taking-out device is composed of an inner sleeve, a push-pull rod, a handle, a metal ring and a filtering object taking-out bag. The length of the inner sleeve is greater than that of a cystscope sheath, the length of the push-pull rod is greater than that of the inner sleeve, one end of the push-pull rod is provided with the handle, the other end is provided with the metal ring, the metal ring is sleeved by the filtering object taking-out bag, the filtering object taking-out bag only can filter liquids and cannot filter tumor cells and tissues, the metal ring is elastic, the push-pull rod, the metal ring and the filtering object taking-out bag can be placed in the inner sleeve, and when the metal ring is pushed out from the inner sleeve, the metal ring is expanded so as to open the bag mouth of the filtering object taking-out bag. The disposable specimen taking-out device provided by the invention has the following advantages: compared to the prior art, the disposable specimen taking-out device is reasonable in structural design, can effectively take operation specimens completely out of bladders, ureters or renal pelvis and renal calyces, does not cause avulsion when the specimens are taken out, is more convenient and rapid to take the specimens out, takes out the specimens completely without residuals, and improves the efficiency and the treatment effect of an operation.