A tool bar, comprising a head part, a tail part, a pipe connection assembly, a backstop mechanism and a bushing member; the head part and the tail part are connected with each other by the pipe connection assembly; the bushing comprises a cone section and a cylinder section; one end of the head part passes through the cylinder section and connected to an inner thread of the cone section; the outer side of the cone section is configured to secure with a tool head; an external thread is provided on an outer surface of the cylinder section; the backstop mechanism comprises an intermediate member and a lock cap; the intermediate member is a hollow cylinder; the lock cap is a hollow cylindrical structure, with an internal thread provided on an inner wall of the lock cap at one end, and a shoulder provided at an end mouth on the other end; the intermediate member is fitted into an interior of the lock cap; the intermediate member and the lock cap together are fitted over the head part; the intermediate member tightly abuts against an outer surface of the head part; the internal thread on the lock cap is coupled with the external thread on the cylinder section; the shoulder abuts against an outer end face of the intermediate member; the pipe connection assembly comprises an inner bush, an outer bush, a lock bush and an intermediate bush; the inner bush comprises a first diameter bush and a second diameter bush, wherein the first diameter bush has a greater diameter than the second diameter bush; the first diameter bush is connected to one end of the bushing member away from the head part; one end of the outer bush is connected to one end of the tail part; the intermediate bush is fitted over the second diameter bush; the outer bush is fitted over the second diameter bush; an end face of the outer bush is jointed with an end face of the intermediate bush; the lock bush is fitted over the intermediate bush and the outer bush; an end of the lock bush is connected to the outer bush by thread connection; a stop collar is provided on the intermediate of the inner wall of the lock bush; when the lock bush is fitted over the intermediate bush and the outer bush, the stop collar is located between the intermediate bush and the first diameter bush. the bushing comprises a cone section and a cylinder section; one end of the head part passes through the cylinder section and connected to an inner thread of the cone section; the outer side of the cone section is configured to secure with a tool head; an external thread is provided on an outer surface of the cylinder section; the backstop mechanism comprises an intermediate member and a lock cap; the intermediate member is a hollow cylinder; the lock cap is a hollow cylindrical structure, with an internal thread provided on an inner wall of the lock cap at one end, and a shoulder provided at an end mouth on the other end; the intermediate member is fitted into an interior of the lock cap; the intermediate member and the lock cap together are fitted over the head part; the intermediate member tightly abuts against an outer surface of the head part; the internal thread on the lock cap is coupled with the external thread on the cylinder section; the shoulder abuts against an outer end face of the intermediate member; the pipe connection assembly comprises an inner bush, an outer bush, a lock bush and an intermediate bush; the inner bush comprises a first diameter bush and a second diameter bush, wherein the first diameter bush has a greater diameter than the second diameter bush; the first diameter bush is connected to one end of the bushing member away from the head part; one end of the outer bush is connected to one end of the tail part; the intermediate bush is fitted over the second diameter bush; the outer bush is fitted over the second diameter bush; an end face of the outer bush is jointed with an end face of the intermediate bush; the lock bush is fitted over the intermediate bush and the outer bush; an end of the lock bush is connected to the outer bush by thread connection; a stop collar is provided on the intermediate of the inner wall of the lock bush; when the lock bush is fitted over the intermediate bush and the outer bush, the stop collar is located between the intermediate bush and the first diameter bush.