Web 2.0 has facilitated an “all people expert” era in the internet world, and users have transformed from pure knowledge receptors to knowledge providers or knowledge developers. In the field of concrete products, users wish to design their own products to show personal creativity. More and more enterprises provide the components or tools of products for users to apply their creativity toward product design, and thus, users can be viewed as another form of designers. Based on the concepts, namely “user is innovator” and “design by user-self”, using LEGO bricks as the design element and LEGO players with high design capability as the research subjects, this study qualitatively implemented “a concept model of highly-involved users’ design knowledge and search approaches,’ and proposed the conceptual tools, including: research questionnaire tools, judgment method for changed attributes, and model construction method and process. This article generalized the key design knowledge and search approaches needed by four types of highly-involved users (junior expert, exhibition participator, business manager, and award winner). With the proposed concept model, feasible suggestions and strategies were offered for users and industries for future development. The possession of design knowledge in users, it not only fulfills individual creativity but also indirectly expands the creativity domain of the enterprise. From the enterprise’s perspective, various development strategies could be made to increase its experience economic value and upgrade its professional image. Through proposed model, the design knowledge and skills of highly-involved users will advance from a few individual hobbies to a creative experience industry and start new design power in the industry.