Conceptual design has a considerable effect on costs of products and product innovation. Therefore, it is known as the most critical phase of engineering design process. We envision that new generation CAD/E systems will hinge on innovative conceptual design. Despite its importance, the relevant works and commercial efforts have usually concentrated on embodiment and detail design, which are the last two phases of engineering design process. Because the conceptual design phase includes time-consuming and tedious methods. Moreover, they do not sufficiently incorporate creativity methods that trigger designers to find more creative and innovative solutions. To cope with this issue, we propose an integration of TRIZ and conceptual design process based on Pahl and Beitz's Systematic Approach. In the proposed integration model, TRIZ is used as a problem solver in the step of determination of problems; as a solution finder in the step of searching for solutions to subfunctions, and as a solution improver after the step of evaluation in the design process. To demonstrate the applicability of the model, a case study is conducted. The case study shows that the integration model is superior to other similar works in terms of inventiveness level, applicability to practice, and efforts to use.