Model transformation (MT) is a key component of model driven software development. It is used to transform source model into a target model, to increase model quality and introduce design pattern and refactoring. As with other software development artifacts, MTs are not free from bugs and thus they must be verified. Various researches have been carried out on model transformation verification approaches, but no one has evaluated their usability. Indirect model checking approach for transformation (IMCAT) is an approach that can verify code generators by model checking the generated code. In this paper a combine usability model to evaluate IMCAT usability related to its learnability, efficiency and effectiveness will be presented. © 2014 IEEE.