A twist beam plays important roles in a trailing twist axle suspension. The cross-sectional configuration of the twist beam determines the performance of the suspension. The finite element (FE) analysis is usually utilized in order to evaluate the performance of this suspension. However, most automotive designers cannot directly perform the FE analysis because specific skills are required to achieve sophisticated operation. Moreover, the construction of the FE model also requires a large amount of time and task. In this paper, we propose a new methodology for the initial design of the trailing twist axle suspension in order to overcome these problems. This method includes (1) the interactive drawing operation for the cross-section, (2) the quick evaluation of the cross-sectional properties, and (3) the automatic construction of the twist beam stiffness matrix used in the kinematic analysis. Further, we introduce a new type of program, Toyota Twist-beam Designer (TTD), based on this new methodology. This program works on Microsoft/Excel, and is easily operated by actual chassis designers. Finally, we confirm the usefulness of this program using simple examples.