Nowadays, software solutions of railway information system were paid attention mainly with comprehensive function, process control, and advanced techniques, ignoring the usability. Regarding to the markets feedback, it was obviously essential to satisfy user experience by client oriented products designed more precisely and accurately. Herein the article proposed a method to evaluate the usability of railway information system software by the combination of the international standard usability measurement model and AHP. The sub-feature of determining the usability of solutions was used to construct the judgment matrix, and calculate its weight, according to the weight value, the precedence of important degree was made. Taking an existing Power Supply and Environment Centralized Monitory System as an example, based on the proposed method, the usability was evaluated by YAAHP.