Abstract: This paper describes SCTI,a computer aided control system design software package.This package can perform a number of functions in the system alaysis and synthesis.And it is quite suitable for the design of the single-input-single-output linearSystems with constant coefficients.The algorithms used in the package have been carefully seleted to ensure stability.This package is very easy to use and can be runon ordinary microcomputers.An example is given to illustrate how the package hasbeen used in practical design.