The invention discloses a water composite material floating body stand system for solar power generation and a manufacturing process thereof. The floating body stand system comprises a plurality of composite material floating body units and a composite material support system; the main body part of each composite material floating body unit is a lattice web reinforced composite material foam sandwich layer, wherein the chemical component of foam is polyurethane, polyvinyl chloride or polyetherimide, a through rectangular hole is formed in the middle of the main body part, the four corners of each hole are not hollowed out apart from the floating body part, butt-joint bolt holes are pre-buried in the periphery of each composite material floating body unit, and the composite material floating bodies are connected into a whole body along the longitudinal and transverse directions; and the composite material support system is a composite material upright post support system or a composite material cylinder support system, and consists of a composite material extrusion sectional material. The system is applicable to the construction of water photovoltaic power stations, and the service life of the whole floating body stand system is prolonged.