This article examines the importance of integrating technical and creative design into the formation and development of cognitive interests of preschoolers. The purpose of the study is to identify the pedagogical possibilities of activating children's engineering thinking through a combination of technical and creative design. The article analyzes the psychological and pedagogical aspects of the concept of cognitive interest and describes the features of the development of constructive activity in preschool children. In addition, the results of experimental work carried out by combining types of technical and creative design are presented. As a result, it was proved that integrated forms of construction are an effective means of developing attention, imagination, logical thinking and cognitive interest in children. Integrated types of construction not only increase children's interest, but also develop their problem-solving skills and implement their own ideas. The results of the study indicate the effectiveness of the organization of a developing environment based on constructive activity in the educational process. The authors provide recommendations on the implementation of STEM pedagogy, design technology and design methods in the educational process in preschool organizations.