The severe space environment is a challenge to the space operation of commercial electronic systems such that space electronic devices and electronic systems must be passed space environment test before space operation. In this paper, the radiation test and analysis of a commercial 32 bit single chip computer MPC555 for satellite onboard computer (OBC) and its electronic devices is discussed. Establishment of a radiation evaluation system for the simulated space environment with measurement of total dose effect, where the radiation source is (Co-60) γ-ray, and evaluating of how much radiation the 32 bit OBC can sustain within its mission lifetime are conducted in this work. Experimental result shows that the MPC555 passes the radiation environment test. These measurement and test can be employed as a reference when the requirement of the radiation total dosage effect is considered for the other satellites electronics subsystems