The enhanced damage was summarized for bipolar devices and bipolar linear circuits in the radiation environment of low dose rate. It could cause the early failure of systems. The physical mechanism of producing failure of low dose rate was analyzed. This is totally different from the damage mechanism of MOS devices caused by ionizing radiation. In order to shorten the time of simulating test and to raise the ratio of effectiveness/spending
several test methods of accelerating simulation were researched. Some points of view were put forward on system hardness assurance at low dose rate.