The invention discloses an execution method of a plate spray process for conducting heat by using cooling fins. According to the execution method, a plate spray device is used; the plate spray device is used for driving a spray head (890) for spraying to move in the spray process; and the plate spray device comprises a support frame (9), a traveling bracket (8) and a spray head bearing part (89), wherein the spray head bearing part (89) is fixed from the upper and lower sides of the traveling bracket (8) and is used for clamping the spray head (890) for spraying, a screw (6), which is driven by a motor (2), is rotatably arranged on the support frame (9) and extends forwards and backwards, penetrates through the traveling bracket (8), and the traveling bracket (8) is capable of moving forwards and backwards under the guidance of a guiderail groove (5) which extends forwards and backwards in the support frame (9).