Display omitted •Multi-structure basic hydrates form in gas mixtures with different stable-structure components.•Composition of gas mixtures leads to the hydrate structure transformation between sI and sII.•The inductive effect and the independent nucleation driving force are mutual restriction.•The modified hydrate method well predicts the formation conditions of multi-structure hydrates. Accurate prediction of hydrate formation conditions is the basis of hydrate related research. The Chen-Guo hydrate model could accurately predict the formation conditions of hydrates. However, the misjudgment of basic hydrates structure makes it unsatisfactory to calculate the system with sI and sII hydrates coexisting. Consequently, we proposed that sI and sII basic hydrates will be formed simultaneously under specific conditions. The structure composition of basic hydrates is influenced by three factors: structure induction, driving force of hydrate independent nucleation and composition of gas mixture. On this basis, we improved the Chen-Guo hydrate model by introducing new parameters and adjusted the true structure composition of basic hydrates. The calculation results show that the average absolute deviation of 201 sets of data can be reduced from 9.33% to 2.74%. The calculation precision of modified method is better than that of the original Chen-Guo hydrate model.