The present invention relates to a method for auto angle setting of an infrared sensor module having a light emitting unit and a sensor unit arranged at least two corners of a display panel, includes the steps of selecting a peak detection mode or a slope detection mode; in the peak detection mode, setting a pixel of in the sensor unit which senses a light quantity as a reference point corresponding to a corner other infrared sensor module is arranged at; in the slope detection mode, analyzing the light quantities of a start pixel block and an end pixel block in the sensor unit and setting a pixel which forms a greatest slope as a start point or an end point; and setting an effective angle of view in the sensor unit with reference to the reference point, the start point, and the end point.