Abstract: Hydroxied acrylate copolymers, a new type of coupling agent applied wheat straw/recycled low density polyethene(LDPE) composites, was synthesized by the process of semi-continuous seed polymerization of emulsion.The effects of polymerizing temperature,initiator system on monomer conversation ratios and reactive stability,the relationship between acrylate copolymers synthesized and the properties of composites manufactured were investigated.The results show that it is impossible to introduce high proportional N-hydroxymethyl acrylamide(NMA)and β-hydroxyl ethyl acrylate (HEA)at the same time,and achieve close 100% monomers conversion ratios and stable copolymerization of no gel with K₂S₂O₈ or K₂S₂O₈/FeSO₄ as initiators.While they can implement to use K₂S₂O₈/FeSO₄/NaSO₂ as initiators. When hydroxied acrylate copolymers synthesized and isocyanate PAPI mixed and used in wheat straw/recycled LDPE composites,the physical and mechanical properties of the composites improved significantly and achieved the standard requirement GB/T4897.7—2003 for heavy-duty load-bearing boards for use in humid conditions.