The invention relates to a sampling point differential protection misoperation prevention method, belonging to the technical field of relay protection of power systems. The method comprises the following steps of: firstly, performing difference calculation to differential current and brake current sampling points, and judging whether the differenced differential current and brake current sampling values meet a rate brake condition, wherein influence of unsaturated CT attenuation direct current component on the synthesized differential current may be weakened through a difference algorithm; and judging whether a criterion for opening sampling point differential protection is satisfied according to ratio of the sampling values of the differenced differential current and brake current. The method solves a problem of misoperation of sampling point differential protection caused by too fast attenuation of the direct component when external fault single CT is saturated and unsaturated CT current contains large direct current component and flows through a low current converter of a protection device. Meanwhile, by the method, sampling point differential protection causes no misoperation when waveform is abnormal, and causes reliable operation when normal failure happens, thus, reliability of sampling point differential protection is improved.