The invention discloses a preparation method for an ultra high molecular weight polyethylene (UHMWPE) fiber/thermosetting epoxy resin high-strength anti-bending composite board. Short UHMWPE fiber yarns are prepared into woven fabrics, after the woven fabrics are subjected to surface chemical treatment and coupling agent treatment, at the normal temperature, thermosetting epoxy resin/curing agent mixed liquor is introduced in vacuum, the woven fabrics are subjected to compression molding, and the composite board with ultra-high tensile failure strength and ultra-high anti-side bending performance is prepared.