The absorbed dose assessment method was developed based on compute unified device architecture parallel architecture and human voxel model, to realize the parallel computing of radiation dose for human body in the radiation environment using the GPU processors and shared memory. The maintenance strategy simulation dose assessment of the spallation target proton beam window for accelerator driven system was tested by this method. The results showed that the computing time can reach 10 ms level with millions of voxel and the dose calculation can synchronize with real-time simulation of maintenance process. This method could realize the requirement of organ equivalent dose and effective dose calculation for maintenance worker. In the simulation deduction of maintenance strategy, this method is of great significance in protecting personnel radiation safety and improving the efficiency for the design and validation of maintenance scheme.Cited