The invention provides a resin-based waterproof plate and a manufacturing method thereof. Plate peaks are formed on the waterproof plate at certain intervals, V-shaped plate grooves are formed among the plate peaks, lower planar segments and lower indent segments are formed alternatively at certain intervals below the waterproof plate, and hollow cavities are formed between the upper side of the waterproof plate and the lower side of the waterproof plate; the waterproof plate and a connecting waterproof plate are connected in a buckling way through buckling plates and mounting screws, upper cambered surfaces are formed on the buckling plates, mounting screw holes are formed in the upper cambered surfaces, lower inserting tips are arranged below the buckling plates, lower slots are formed between every two adjacent lower inserting tips, and hollow cavities are formed between the lower inserting tips and the upper cambered surfaces. The manufacturing method is implemented through resin-based raw material burdening, waterproof plate drawing, extruding and forming, field assembly and a construction process. The resin-based waterproof plate has the characteristics of corrosion prevention, waterproofness, high intensity, high structural property, realization of mechanical production and easiness in construction, and is suitable to be applied in the production and construction of waterproof plates in the fields of electric power and buildings.