The invention discloses a servo drive multi-rod type variable-degree-of-freedom mechanical arm used for transport work. The servo drive multi-rod type variable-degree-of-freedom arm used for the transport work is composed of a base 1, a driving rod 13, a first connecting rod 15, a first connecting piece 5, a fourth connecting rod 4, a big arm 2, a wrist connecting rod 6, a second connecting rod 22, a third connecting rod 26, a wrist 27, a vacuum sucking disc 28, a servo driving device, a first locking device 23 and a second locking device 24; the big arm 2 is connected to the base through a first revolute pair 10, the first locking device 23 and the second locking device 24 are installed on a seventh revolute pair 16 and an eleventh revolute pair 19 respectively, and the servo driving device comprises a first servo motor, and is connected to the driving rod 13 to drive the rotation of the driving rod 13; the first locking device 23 and the second locking device 24 are locked through an electromagnetism mode. According to the servo drive multi-rod type variable freedom mechanical arm used for the transport work, a connecting rod transmission mechanism is adopted to replace a hydraulic mechanism, the disadvantages that the hydraulic mechanism is prone to oil leakage and the mechanism is complicated are solved, through the adoption of a locking device on the revolute pair, different working conditions, and the quantity of the adopted motors is smaller than that of the degree of freedom of the mechanism.