In order to improve the sensing precision of fiber Bragg grating sensor and reduce the influence of temperature on the cross-sensitivity of the pressure sensor, a rhombic pressure change sensor with self-temperature-supplementing was proposed. The ANSYS softwave was used to analyze the property of static force and heat of the rhombic structure by the finite element method. The influence of the side length and thickness of rhombic structure on the sensitivity were studied through the mechanism of self-temperature compensation. The side length and thickness of the sensor were determined to be 7mm and 1mm by simulation. At the same time, the simulation experiment also proves that the rhombic structure has the temperature self-compensation, and the final design of the sensor's micro-shape variable can be as low as 7.9669×10-8mm. Compared with traditional sensors, it can perform temperature compensation and strong anti-interference ability, which can be used in detecting local stress, engineering structural defects, and aerospace sensing.