Alcoholized ethylene-vinyl acetate copolymer (EVAL) was chemically modified by grafting n-alkyl acrylates with different alkyl chain lengths. The grafted EVAL was characterized through Fourier transform infrared (FTIR) spectroscopy, H-1 and C-13 nuclear magnetic resonance (NMR) spectroscopy, and element analysis. The effect of grafted EVAL on wax crystallization process of crude oil was investigated by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). The results showed that the length of alkyl side-chain in grafted EVAL largely influenced the efficiency of grafted EVAL. Grafted EVAL with side-chain length of C-16 could reduce the pour point of Shengli (SL) crude oil by 11 degrees C, and that with side-chain length of C-18 could reduce the pour point of Jianghan (JH) crude oil by 14.5 degrees C. The introduction of alkyl side-chain could improve wax solubility and promote grafted EVAL to adsorb and cocrystallize with wax molecules, which obviously decreased the wax precipitation amount and changed the wax crystallization process.