The utility model discloses a simple pipeline flange welding positioning device. The simple pipeline flange welding positioning device comprises a fixed trolley, a track movable trolley abutting against the fixed trolley, at least two sets of positioning clamping blocks installed on the track movable trolley and a fixed baffle. The fixed trolley can be used for positioning a straight-through pipeline flange and also used for positioning an elbow flange; the rail trolley is mainly used for positioning and fixing the straight-through pipeline; the machine tail fixing baffle is used for positioning the other side of the straight-through pipeline. When 90-degree elbow flange plates are welded, the right-angle steel plate can be directly used for right-angle positioning of the flange plates onthe two sides of the elbow, a plumb bob does not need to be hung, and measuring tools and sample plates are omitted. A flange plate is hung on the elbow and is directly positioned by spot welding. Thestraight pipe or the elbow positioned by the device through spot welding completely conforms to the design, time and labor are saved, and waste products are not discharged. A hoisting frame is additionally arranged at the top of the trolley and can assist hoisting of large steel pipes, and labor intensity of workers is reduced.