The invention discloses a modifier for the mechanical properties of a rubber-plastic product. The modifier is directed at the defects of conventional rubber-plastic products and is composed of the following preparation raw materials: resin, polyethylene, a silane coupling agent, a carboxylic acid compound, a water reducer, an epoxy compound, phosphite, a flexibilizer, a plasticizer, a wear-resisting agent, etc. The modifier for the mechanical properties of the rubber-plastic product is free of toxicity and harm and has good weatherability and stability; and when the modifier is applied to a rubber-plastic product, the obtained product has good flame retardation performance, wear resistance, tensile properties and strength, can maintain good mechanical properties and is not prone to deterioration and damage when used in a high temperature environment for a long time, and has long service life and a good practical value.