Model-based development is a software development method in which models are created before source code is written. Although the method is effective, we have to modify models when we face evolution such as change of platforms. These modifications crosscut over many places in the models, and tend to cause unexpected errors. In order to tackle this problem, we propose a method for model evolution using model transformations based on aspect orientation, a mechanism that modularizes crosscutting concerns. A modeler can extend model transformation rules by defining new aspects in the process of modeling. In this paper, we demonstrate the effectiveness of aspect orientation in terms of model evolution.