Abstract: This article introduces the development process of a safety controller for construction machinery, the development process and safety controller meet the requirements of IEC 61508 SiL2 and ISO 13849 PL d, Cat.3 requirements. The controller includes dual cores: one for standard function and the other for diagnostics and they communicate with each other through SPI. In the hardware design, the power supply part realizes the automatic detection of overvoltage, undervoltage and other abnormal states, All analog and digital input channels meet the 1oo2 architecture (ISO 13849) and all power output channels have two shutdown paths, the power output channel has two close paths. The bottom software of the safety and non safety related functions of the firmware is completely isolated to improve the reliability of the controller.