Abstract: Acrylic polymers with different ester side chains were synthesized by emulsion polymerization and then blended with natural rubber (NR) latex with various mass fractions (w=5%, 10% and 15%) to study the effect of ester side chain structure on the compatibility of acrylic polymer latex and natural rubber.The results showed that with the dosage of 10% the latex film modified by polymer with the largest number of alkyl groups and the longest ester side chain showed the largest tensile strength,tear strength,hardness and elongation at break but the minimum tension set.Upon increasing amount of alkyl groups and length of ester side chain on the polymer,the surface of blend film became even and smooth,the fracture of the films became dense and precipitate free and the glass temperature of blend films increased,suggesting the continuous increase in the mutual diffusion between two phases of the blends.Finally,a modified film material with excellent properties was obtained.