The utility model provides a holding vessel drain mediation drainage device, relate to the petroleum and natural gas exploitation field, this holding vessel drain mediation drainage device includes abearing section of thick bamboo and through rod, a bearing section of thick bamboo has hollow inner chamber, through rod follows the axis setting of inner chamber and runs through the terminal surfaceat bearing section of thick bamboo both ends, through rod can follow the axis reciprocating motion of a bearing section of thick bamboo, the one end of a bearing section of thick bamboo is held for the operation, the other end of a bearing section of thick bamboo is for getting into the end, still set up the discharge port with the inner chamber intercommunication on the outer wall of a bearing section of thick bamboo, holding vessel drain mediation drainage device is still including the coupling assembling who connects a bearing section of thick bamboo and holding vessel blowdown valve, coupling assembling sets firmly on the outer wall that gets into the end. This holding vessel drain mediation drainage device can dredge the plug in drain skirt and the blowdown gate, and the remaining oil water mixture in the guide holding vessel is outside drain skirt outflow holding vessel.