The utility model discloses a button formula fixable drainage bag relates to drainage bag technical field, the utility model discloses a drainage bag, the drainage bag outer wall is provided with fixed establishment, the drainage bag top is provided with the docking mechanism, the utility model discloses a clamping block has been set, when needing to fix the position of drainage bag, first place the drainage bag to the position below the wound on the patient's body, then align the fixed casing with the sliding slot, slide to the inside in the sliding slot, in this process, the clamping block will be clamped into the clamping groove, but because the clamping block is the design of inclined plane, so when the clamping block slides out of the clamping groove, will drive the fixed plate to remove to make the fixed axle remove, this mechanism can fix the drainage bag on the patient's body, ensure that it will not fall or change position because of moving or other external factors in the use process, can make the patient more conveniently carry out daily activity, reduced the interference to the drainage bag.