Abstract: A new linear block diagram approach is presented for digital simulation of linear systems. Owing to use a typical block in which numerator and denominator are both second order, it becomes more general and more usable. The mathematical expression of transforming linear block diagram into state equation is derived. The procedure for calculating the exponential matrix guarantees that the simulation accuracy is not restricted by the calculating step length, then the calculating efficiency has been raised greatly. Many types of input function are provided. The initial conditions can be added to any block. The Approach is very suitable for engineering applications.