A barcode decoding method includes steps of analyzing a relative relationship between at least two characteristic points of a gray level distribution of a target scanning line of a target barcode to obtain at least one reference characteristic parameter; when determining a current distance between a barcode reader and the target barcode being a relatively long distance, dividing the gray level distribution into at least one bar area and at least one space area; setting a gray level region and locating at least one peak point and/or at least one valley point located within the gray level region from the gray level distribution; when the peak point is located within the bar area, interpolating a space corresponding to the peak point into the bar area; and when the valley point is located within the space area, interpolating a bar corresponding to the valley point into the space area.