From 2007 to 2012, at Nha Ho Research Institute for Cotton and Agricultural Development, CryIAc gene were transformed into 4 cotton cultivars (C118, LRA5166, MCU9 and TMl) by microinjecting via pollen tube pathway (PTP). The study determinro two essential parameters, including microinjection time was from 6 to 8 hours of the second day after blooming and length of needle to syringe into ovary of C118, LRA5166, MCU9 and TM1 cultivars were 0.72, 0.62, 0.74 and 0.78 em respectively. Three solutions containing 10, 20 and 30 ug/ml DNA plasmid (pIBT-CryIAc) were microinjected into 14,375 flowers and produced 144,395 T0 generation transgenic seeds. Screening and evaluating transgenic plants (by kanamycin resistance, PCR and insect bioassay) 80 bollworm resistant transgienic lines have been obtained at T2 generation (7 lines of LRA5166, 64 lines of MCU9 and 9 lines of TM1), 50 lines of which were high bollworm resistance (7 lines of LRA5166, 38 lines of MCU9 and 5 lines of TM1). The average transgenic plant frequency of this study was 0.1 percent. The transgenic plant frequency of C118, LRA5166, MCU9 and TM1 cultivars were 0, 0.03, 0.54 and 0.05 percent respectively. The transgenic plant frequency of 10, 20 and 30 ug/ml DNA plasmid concentrations were 0, 0.26 and 0.05 percent respectively.