The invention provides a device for machining a left heald loop of a jacquard heald, belongs to the field of textile equipment, and aims to machine the left heald loop, which belongs to the jacquard heald, has a required shape and function, and is applied to a jacquard machine, through the designed device. The device mainly comprises a twisted weaving mechanism, a gear train and a reverse rotating mechanism. When the device works, to-be-machined wires are put into a lower die at first; then, a roller on a left cam is pushed through the rotation of the left cam, so that an upper die can be driven by an upper die swinging arm for die assembly and die disassembly; meanwhile, a semicircular part is driven by an upper die stirring plate to press the wires into a die; then, through the rotation of a twisted weaving shaft, a twisted weaving die fixing frame and the die are driven to rotate for twisted weaving, and the reverse rotation is achieved through reverse rotating cams; and finally, the die is opened and a twisted weaving process is finished. According to the device, the speed ratio of all shafts is guaranteed through the gear train on the left side. The device is mainly applied to machining of the left heald loop, which belongs to the jacquard heald as well as has such shape and function.