Being applicable to X ray scan imaging device in areas of safety check, medical examining, non destructive test in industry etc, the disclosed X ray source is composed of expansion part, positive dual voltage sampling circuit area, X ray tube placement area, negative dual voltage sampling circuit area and seal socket. The positive and negative dual voltage sampling circuit areas are distributed on two ends symmetrically. X ray tube is located on central line. Features are: easy of preparing protection of high voltage insulation, convenient for maintenance, reduced weight and evenness of quality within emergence angle of X ray.