The invention relates to the field of 
medical instruments, and particularly to an improved drainage device special for the 
thoracic surgery department. The improved drainage device special for the 
thoracic surgery department comprises a hydrops 
bottle, wherein the cover body is in threaded connection with the upper end of the hydrops 
bottle, and the negative pressure air bag 
assembly is communicated with the 
effusion bottle through a negative pressure 
catheter. The right end of the negative pressure guide 
pipe penetrates through the cover body and extends into the upper part of the 
effusion bottle; a hydrops conduit is arranged at the left part of the cover body; the left end of the 
effusion guide 
pipe penetrates through the cover body and extends into the upper part of the effusion bottle; a buffer ball is connected to the right end of the hydrops 
catheter, a liquid outlet 
pipe in 
interference fit with the right end of the hydrops 
catheter is arranged on the lower portion of the buffer ball, a liquid inlet pipe in 
interference fit with the left end of the drainage pipe is arranged on the right portion of the buffer ball, and a dredging 
assembly is connected to the left portion ofthe buffer ball through a 
threaded pipe and comprises a 
piston pipe; the drainage device is simple in structure, low in cost, convenient to use, convenient to disassemble and assemble and convenient to clean and disinfect, meanwhile, the dredging frame is driven to penetrate into the drainage tube by continuously pressing the small air bag, the drainage tube is dredged, and therefore the drainageeffect of hydrops is improved.