The invention relates to a modified master batch used in a multifunctional agricultural greenhouse, which is made by activating, stirring, mixing and screening polyolefin, sericite, a light stabilizer, a heat stabilizer, an antioxidant, an anti-flow-dripping agent and a dispersant. The modified master batch of the invention can improve the tensile strength of plastics, strengthen the toughness of products and resist aging and cracking. As to reinforced thermoplasticity plastics, the modified master batch is characterized by high strength, large filling volume, good acid-base corrosion resistance, penetration and dielectric property, low thermal expansion coefficient and flammability, short period of transverse compression, planar enhancement, low abrasion and low wear of processing equipment; as to reinforced thermosetting plastics, the modified master batch has good dielectric property, good size stability, improved hardness and heat distortion temperature as well as good penetration and insulation. In addition, the modified master batch also has good dissolubility and can be compatible with a great deal of fillers such as talcum powder, calcium carbonate, etc.