Abstract: This paper presents an estimate method on radiationinduced charge effect from LC4007A and LC4007B device in lowdose space environment. According to the result, on the basis of MILSTD 883C, Test Method 1019.4, 60Co irradiation plus 25℃ annealing can provide effects of oxidetrip charge on MOS device response in space that is estimated significantly less conservative than MILSTD 883C, Test Method 1019.4. The possible phenomena of oneweek hightemperature anneal in MILSTD 883C, Test Method 1019.4 detecting interfacetrip related failures in MOS devices were discussed.