ABSTRACT The increase in design depth of deep-sea equipment leads to new requirements for material selection criterion, so it is necessary to pay attention to the rationality of the coefficient values in the design formula based on material performance. In this paper, based on three candidate high-strength materials, TC4, Ti80 and 18Ni(250), a number of pressure-resistant cylindrical shell calculation models are designed according to the pressure vessel code, and the physical correction coefficients, Cs, in the calculation of the ultimate strength of the cylindrical shells are derived through theoretical and finite element calculations. The results are compared with the curve recommended by the China Classification Society as well as finite element analysis results. The deviations and material suitability between different methods are clearly demonstrated. The theoretical calculation basis for three alternative materials for pressure-resistant shells is extended, thus compensating for the small range of material applicability in current submersible specifications.