The invention is suitable for the field of power generation and provides a method and device for screening power oscillation caused by power system stabilizer abnormality. The method comprises the steps of judging whether an operating state of a PSS is abnormal or not during power oscillation of a unit; if not, determining that the power oscillation of the unit is not caused by abnormal operation of the PSS; if so, judging whether output of the PSS plays a negative damping role in oscillation or not; if so, determining that the power oscillation of the unit is caused by abnormal operation of the PSS; and if not, determining the power oscillation of the unit is not caused by abnormal operation of the PSS. According to the method and the device, whether the PPS in the power oscillation of a generator normally operates or not can be effectively analyzed and whether the output of the PSS plays the negative damping role in oscillation or not can be effectively analyzed, so that the root cause of the power oscillation of the generator is found out, a basis is provided for formulating a solving scheme, a hidden danger of oscillation of the unit is timely eliminated, manpower and material output for taking special monitoring measures on the oscillation unit is avoided, and meanwhile, safe operation of a power grid is also ensured.