A support device for heat dissipation module provides a frame with four corners thereof extending outward a support part respectively. A mounting opening is disposed at the central area of the frame with two opposite side of the mounting opening having a projection plate respectively. A facial side of the projection plate is provided with fitting pins to fit with a guide heat plate and covering the mounting opening without help of welding. Therefore, thinner guide heat plate can be used for simplifying manufacturing process and lowering production cost.