Most engineers and even scholars can not fully understand advanced constitutive models

which brings great difficulties to the integration of theory with practice. In this paper

the elastoplastic model SIMSAND for granular material is taken as an example of constitutive models to develop a simple tool for modeling soil tests. Firstly

the development environment of MATLAB GUI is briefly introduced

and then the steps of interface development are described step by step such as overall layout design

control parameter input design

tick box design

result display design

control button design

error or warning prompt design. In order to study and train the readers

three cases are selected to study the conventional undrained triaxial test

the conventional triaxial drained test and the triaxial drained test with constant mean stress. Starting from the plastic multiplier

three key formulas with pseudo codes are derived and presented with modifications. The detailed development process and key source program of this tool platform will help readers to imitate and train

and provide examples and support for research and teaching in practice of constitutive modeling.