In response to the complex and high radiation level environment at a nuclear accident site, as well as the safety risks and inefficiency of manual monitoring and inspection, a smart mobile robot equipped with X and γ radiation dose rate modules is designed. The mobile robot integrates advanced nuclear radiation sensors, high-precision 3D laser radar, monocular or multifocal cameras, and intelligent motion control systems, enabling autonomous navigation or remote operation in complex and variable nuclear radiation environments. It can measure the real-time and precise radiation dose rate. By integrating these data, the robot can dynamically build and continuously update the radiation dose point cloud map, providing workers with a comprehensive and intuitive distribution of radiation environment information. The method was tested in simulated nuclear radiation environments and actual nuclear industrial sites, verifying its effectiveness and feasibility. The comparison of measurement field data with high-precision simulation models indicates that the method can accurately measure radiation doses and have stability and reliability in complex radiation environments.