Matrix rectifier (AC-DC MC) is a four-quadrant AC-DC power converter device with compact topology. This paper concerns the influence of abnormal power supply conditions to the matrix rectifier. The input and output performances of matrix rectifier with pure sinusoidal supply voltages are discussed. The input currents are symmetrical sinusoidal without any low-order components. But due to the absence of DC capacitors, the abnormal conditions at input side affect the input and output performances directly, which introduce ripples into the DC output and cause the distortion of input currents. In this paper, the low-order harmonic components in input currents, and ripples at output side are theoretically analyzed under conditions that the input voltages are unbalanced and non-sinusoidal respectively. The simulation research is carried out to verify the theoretical analysis, and the results, which demonstrated the analysis conclusions, are given.