The invention discloses a seabed observation node power supply module heat dissipation apparatus. The seabed observation node power supply module heat dissipation apparatus comprises at least one arc-shaped heat dissipation sheet; a power supply module is mounted on the inner wall of the arc-shaped heat dissipation sheet; the two ends of the arc-shaped heat dissipation sheet are fixedly connectedwith a front circular ring and a back circular ring respectively; the arc-shaped heat dissipation sheet is sleeved with a cylindrical cabin body; the two ends of the cylindrical cabin body are open; and one end of the cylindrical cabin body is connected with a front end cover in a sealing manner through the front circular ring while the other end is connected with a back end cover in a sealing manner through the back circular ring. By virtue of the cylindrical cabin body provided by the invention, the power supply module can perform effect heat dissipation in a high load condition, and the service life of instrument is prolonged.