The invention discloses a high-strength and high-toughness flame retardant and smoke suppressing PVC wood-plastic foaming composite building template and a preparation method thereof. The high-strength and high-toughness flame retardant and smoke suppressing PVC wood-plastic foaming composite building template is prepared from PVC resin, an organic filler, a flame retardant, a coupling agent, a foaming agent, a foaming adjuster, a composite stabilizer, a lubricant, a plasticizer, a processing modifier, a flexibilizer MBS resin and an ultraviolet absorbent. By the adoption of the MBS flexibilizer, the impact strength of a product is enhanced, and the compatibility and the processability of the product are further improved. The high-strength and high-toughness flame retardant and smoke suppressing PVC wood-plastic foaming composite building template is prepared by a one-time forming process which is simple and feasible; an experiment shows that the performance of the prepared high-strength and high-toughness flame retardant and smoke suppressing PVC wood-plastic foaming composite building template is much higher than that required by a common building template, can meet the standard of grade I in China on wood-plastic building templates, and can be recycled for 30 times, and wastes can be recycled and remolded to achieve the effects of recycling and zero loss; furthermore, the requirements on energy conservation and environment protection in China are met, and the PVC wood-plastic foaming composite building template has considerable economical benefits.