The utility model discloses a drainage bag convenient to collect drainage liquid and not easy to fall off at the liquid outlet end, which comprises a main body unit and a positioning unit, the main body unit comprises a drainage bag body, the top of the drainage bag body is fixed and communicated with a drainage tube, and the drainage tube is fixed and communicated with a shunt tube. The rubber plug is pulled out from the
discharge tube by shifting, so that liquid in the drainage bag body can be discharged from the
discharge tube, the mode is more convenient, force cannot be applied to the drainage bag body, the drainage bag body is prevented from falling off, and when a drainage liquid sample needs to be reserved for corresponding detection, the drainage tube is blocked by using the second adjusting valve firstly, and then the drainage tube is blocked by using the second adjusting valve. When the sampling device is used, the
syringe head is inserted into the
syringe head sleeve, then the first adjusting valve is opened, drainage liquid flows into the
syringe through the drainage tube and the flow dividing tube, and therefore sampling is completed, compared with an existing mode that a
syringe needle is used for
puncturing the drainage tube, the mode is
safer, damage to the drainage tube is avoided, and follow-up use of the drainage tube is not affected.