The invention discloses a portable multi-jacking multifunctional high-tensile reinforcement bar bending and straightening machine and an operation method thereof. A jack is adopted as a power mechanism. A vertical handle is arranged on the side wall of a body of the jack. A transverse handle is arranged on a sealing flange of the jack. A detachable bender is arranged at the tail end of an ejector rod of the jack and comprises two slots with different radiuses and a right-deflection-angle slot. A support comprises two symmetrical supporting frames and a reinforcement transverse connector between the two supporting frames. The bottoms of the two supporting frames are provided with supporting bases with steel bar grooves. The plane where the two supporting frames are located is located below the plane where the ejector rod is located. The tops of the two supporting frames are fixedly connected with the sealing flange. The device can carry out bending, straightening construction and preformed deflection angle abutting construction on high-tensile reinforcement bars rapidly, is provided with multiple operation ends, has the good using performance and sufficient power, and can be applied to on-site steel bar abutting, bending, straightening and other procedures such as bending and straightening construction similar to drilling pile horn mouth standard bend manufacturing.