High-efficiency pour point depressants (PPDs) for diesel fuel were obtained using a series of tetradecyl methacrylate-N-alpha-methacrylamide copolymers (C14MC-NMLR) with different molar ratios synthesized through radical polymerization of tetradecyl methacrylate (C14MC) and various forms of N-alpha-methacrylamide (NMLR, R = -phenyl, -naphthyl, -cyclohexyl, -14a, -16a, -18a). The copolymers were characterized by Fourier transform infrared spectroscopy, H-1 nuclear magnetic resonance, and thermogravimetric analysis. Results showed that diesel treated with C14MC-NML-phenyl (9:1) and C14MC-NML-14a (6:1) presented better cold flow properties at 2000 ppm, and the reductions in cold filter-plug point (Delta CFPP) and solid point (Delta SP) were (23 and 10 degrees C) and (22 and 11 degrees C) at 2000 ppm, respectively. The depressive effects further improved after compounding. When they were combined at a 1:4 mass ratio, PPDC-6 presented the best depressive effects, and the Delta CFPP and Delta SP reached 25 and 11 degrees C at 1000 ppm dosage and 28 and 15 degrees C at 2000 ppm dosage, respectively. Additionally, the crystallization behavior and crystal morphology of each treated diesel were explored.