The invention provides a method for calibrating and correcting errors of a light quantity sensor. The method comprises the following steps: allowing the light quantity sensor to receive illumination referring to a maximum brightness value; acquiring an actual light quantity value according to the illumination; reading an actual calibrating factor in a micro-processor of the light quantity sensor and acquiring the acquired actual light quantity value, and considering the ratio of the actual calibrating factor to the actual light quantity value to be a constant; re-calculating according to a to-be-calibrated target light quantity value and the ratio of the actual calibrating factor to the actual light quantity value in order to obtain a target calibrating factor; writing the target calibrating factor in the micro-processor of the light quantity sensor. By writing the obtained target calibrating factor as a calibrating factor used by the light quantity sensor subsequently, in the light quantity sensor, the light quantity measured by the light quantity sensor is all calibrated by the target calibrating factor, so that the light quantity sensor is calibrated, and the method has the characteristics of being simple and efficient.