Abstract: This paper presents a new way to evaluate the SEU performance of ASIC internal memory by using Memory-Build-In-Self-Test(MBIST) technology, while an statistical method of effective irradiation dose for MBIST was studied and developed. At last, a SEE verification test was carried out on the heavy ion accelerator by using this method. By comparing with SRAM of the same structure, the results show the error between MBIST(effective irradiation dose 1.27E+7icons/cm²)and SRAM (irradiation dose 1.0E+7icons/cm²) is less than 2 times, which means the MBIST method can be used for evaluating the SEU performance of ASIC internal RAM conveniently and accurately.