The utility model relates to a chain round pin axle puller, include manual hydraulic jack, manual hydraulic jack's cylinder body front end is equipped with the screw thread lead screw, and the inner chamber of screw thread lead screw is equipped with the plunger rod, and manual hydraulic jack's rear end is equipped with the pressurization handle, and screw thread lead screw top spin has connect the ring flange, and it has the bolt and pass through nut fixed joint to peg graft respectively in the two upper and lower through-holes of ring flange, and the other end of two bolts inserts respectively in two through-holes in the upper and lower direction of cross and passes through nut fixed joint, and the horizontal direction axis of cross is on a parallel with waits to tear open chain place plane, round pin crown of roll piece is installed to the front end of plunger rod, and round pin crown of roll piece length direction's axis is the level form and is on a parallel with the horizontal direction axis of cross, and the symmetry is equipped with two counter bores on the preceding terminal surface of round pin crown of roll piece, and it has round pin crown of roll pole to peg graft respectively in two counter bores, and the centre-to-centre spacing of two round pin crown of roll poles is the same with the chain pitch of waiting to tear open the chain. Chain round pin axle can be dismantled fast safely to this puller, prolongs the life of chain.