Abstract: The low abundance isotope ²³⁶U is easily disturbed by strong peak tails in the measurement of Mass Spectrometry. So, the measurement of ²³⁶U is amended with the Background Amendment (BGA) tail calibration method and the dynamic background method. BGA method was used to measure the signal at 235.5 and 236.5 mass number, these signal could be regarded as strong peak tails which was eliminated in the measurement data. When ²³⁶U abundance was low, BGA calibration method had good effect, the emendation to measurement reached 2.24%, the amended value was more close to nominal value, and the effect of dynamic background amendment method is not significant.