The utility model discloses a post porcelain insulator torsional stress strain test system. The system comprises right-angle strain rosettes, a bridge box, a dynamic strain gauge and a computer. The two right-angle strain rosettes are of the same specifications and are fixed on a porcelain post of an umbrella root of a post porcelain insulator, strain gauges on two sides of each strain rosette respectively form an angle of 45 degrees with the axis of the porcelain post, and the two right-angle strain rosettes are symmetrical about the axis of the porcelain post and are 180 degrees away from each other on the same circumference. The four strain gauges of the two right-angle strain rosettes form a full bridge circuit, and are connected to the bridge box by wires. The bridge box is connected with an input terminal of the dynamic strain gauge by a data line, and an output terminal of the dynamic strain gauge is connected with a USB interface of a computer by a data line. A collection control software on the computer can display the size and change of the torsional stress strain at a position to be tested of the post porcelain insulator in real time. The system provided by the utility model can accurately monitor the stress strain of a point to be tested on the surface of the post porcelain insulator in real time, facilitating the prevention of fractures of the post porcelain insulator.