Abstract: Objective To improve the viral packaging titer for production of chimeric antigen receptor T cells (CAR-T)，compare and identify the effective plasmid transfection reagents for viral packaging. Methods Two kinds of retroviral packaging plasmids were transfected by calcium chloride, TransintroTM EL (EL), liposome Lip2000. The transfection efficiency of the three reagents was detected by fluorescence microscopy and flow cytometry. Results EL has achieved relatively high transfection efficiency about MIG1 and MIG2, with up to 49.3% and 43.2%. While the transfection efficiency of liposome Lip2000 was relatively low, with MIG1 of 5.5% and MIG2 of 9.8%. The transfection effect of calcium chloride for the two plasmids was different under the same transfection system, with MIG1 of 2.5% and MIG2 of 54.3%. Conclusion viral packaging for production of CAR-T cells, EL reagent can obtain stable and higher transfection efficiency.