【目的】 棉铃虫Helicoverpa armigera（Hübner）对Bt（Bacillus thuringiensis）的抗性问题是阻碍Bt抗虫棉持续发展的关键，探究棉铃虫对不同Bt蛋白的抗性演化趋势及交互抗性，可为选择合适的抗虫棉花备选基因提供参考。【方法】 在室内通过连续多代筛选，获得了5个对Bt具有不同抗性的品系，利用饲料混合法测定了这些品系棉铃虫的交互抗性。【结果】 经筛选后棉铃虫对Cry1Ac产生了超高水平的抗性、对Cry2Ab、Vip3Aa产生了超低抗性（耐性）；Cry1Ac抗性棉铃虫停止筛选而换成Cry2Ab或Vip3Aa继续筛选后，棉铃虫对Cry1Ac抗性水平明显降低，对Cry2Ab或Vip3Aa产生低抗或超低抗性（耐性）。Cry1Ac抗性棉铃虫对Cry1Ab敏感性显著降低，而对Cry2Ab、Cry2Ah及Vip3Aa敏感性变化不显著；Cry2Ab抗性品系棉铃虫对Cry1Ac敏感性显著降低；Vip3Aa抗性品系棉铃虫对Cry1Ac敏感性变化不显著。说明Cry1Ac与Cry1Ab间存在明显交互抗性，与Cry2Ah、Vip3Aa没有交互抗性；而Cry2Ab与Cry1Ac间存在不对称的交互抗性。【结论】 在筛选新杀虫基因或叠加基因时，应充分考虑抗性发展及交互抗性问题，Cry2Ah、Vip3Aa是治理Cry1Ac抗性棉铃虫或与Cry1Ac叠加最优的选择。

[Objectives]  The development of resistance to Bt (Bacillus thuringiensis) toxins by Helicoverpa armigera (Hübner) is the main constraint on the continuous planting of Bt transgenic cotton. In order to choose appropriate, alternative Bt genes to incorporate into transgenic cotton, we studied the resistance, and cross-resistance, of H. armigera to different Bt proteins. [Methods]  After successive selection in the laboratory, we obtained 5 Bt-resistant strains with different resistance levels and determined the cross-resistance of these strains to different Bt proteins. [Results]  Selection produced a strain of H. armigera with ultra-high resistance to Cry1Ac but low resistance (tolerance) to Cry2Ab and Vip3Aa. When Cry1Ac-resistant H. armigera were selected for resistance to Cry2Ab or Vip3Aa their resistance to Cry1Ac decreased significantly. Selection could only produce low, or ultra-low, resistance (tolerance) to Cry2Ab or Vip3Aa. The susceptibility of H. armigera to Cry1Ab dropped dramatically in the Cry1Ac-resistant strain, however, its susceptibility to Cry2Ab, Cry2Ah and Vip3Aa did not change significantly. The susceptibility of Cry2Ab-resistant H. armigera to Cry1Ac decreased significantly while the susceptibility of Vip3Aa low-resistant larvae to Cry1Ac did not change. Overall, the present study indicates obvious cross-resistance between Cry1Ac and Cry1Ab, but no cross-resistance between Cry1Ac and Cry2Ah or Vip3Aa. However, asymmetrical cross- resistance was found between Cry1Ac and Cry2Ab. [Conclusion]  The evolution of resistance and cross-resistance in H. armigera should be fully considered when selecting novel, insecticidal genes for transgenic cotton. We suggest that Cry2Ah and Vip3Aa are the best choices for incorporation into new transgenic cotton varieties.