The invention discloses a fixture capable of achieving pin shearing and forming through one step. The fixture is characterized in that a support is included, the top of the support is provided with a pressing mechanism, and the bottom side of the support is provided with a work table; the upper surface of the work table is provided with a fixing part, the side of the fixing part is provided with a lower knife part, and a female die is arranged in the lower knife part; the bottom of the pressing mechanism is connected with a guiding device, and the bottom of the guiding device is connected with an upper knife part; the bottom of the upper knife part is provided with a male die matched with the female die; the same sides of the upper knife part and the lower knife part are provided with an upper cutting edge and a lower cutting edge respectively. The fixture capable of achieving pin shearing and forming through one step has the advantages of being simple in structure, high in controllability and capable of adapting to pipe fittings with two pipes and three pipes and simultaneously achieving shearing and forming through one step and has the better forming effect, and therefore the production yield of a manufacturer is increased.