The midgut of lepidopteran larvae serves as a target for many pathogens such as Bacillus thuringiensis (Bt). Cell lines originating from midgut tissues will be very helpful tools in many research fields. However, to date, no Bt-susceptible midgut-derived cell lines are available. Here, we reported that a novel cell line, designated as HNU-Ha-MG1, was established from midgut tissue of the fourth instar larvae of Helicoverpa armigera. This cell line grew well in Grace's insect cell culture medium supplemented with 10-15% fetal bovine serum. The shape of the most cells was round or polygonal, and some tended to aggregate to form multiple cell masses. The size of the cells was 13.8 ± 1.8 μm in diameter, and the maximum density reached (2.40 ± 0.15) × 10(6) cells/ml. The population doubling time during logarithmic growth phase was 58.6 ± 7.0 h at 28°C. The number of chromosomes was about 90-130, which exhibited typical chromosome characteristics of lepidopteran cell lines. The patterns of random amplified polymorphic DNA of the cell line were different from those of Sl-HP and Hi5 cell lines which were frequently used in our laboratory. 20-Hydroxyecdysterone induced apoptosis in a very small part of cells at 2 μg/ml but did not affect expression of autophagy-related protein 8 (Atg8) and its lipidation at 36 h post-treatment. The cell line was permissive to Autographa californica nuclear polyhedrosis virus (AcMNPV) and H. armigera nuclear polyhedrosis virus (HaSNPV). This cell line was found to be susceptible to activated Cry1C at the final concentration of 0.5-1.0 μg/ml but not to the activated Cry1Ac.