A support apparatus for a photovoltaic module and a photovoltaic system are provided. The support apparatus for a photovoltaic module is to be arranged on a water surface, and includes: a support body for mounting the photovoltaic module; and a floating body connected to the support body and configured to provide buoyancy for the support apparatus. A connection function for providing connection with the photovoltaic module and a buoyancy function for providing the buoyancy are separated. The support body having the connection function may be used for providing only connection with the photovoltaic module and not for providing buoyancy. In manufacturing and installation processes, it is unnecessary for the support body to be watertight, thus the manufacturing process of the support body may be greatly simplified, and the manufacturing cost can be reduced.