Critical thinking skills is one of the competencies required of students. Criticalthinking is one character that lately has become the issue of education, in addition to beingpart of the process of forming the morals of the nation. To increase the critical thinking skillsstudents need to be learning innovation. Based on that idea, the researchers will conductresearch effort to improve students' critical thinking skills Mathematics Education Faculty ofScience and Technology using teaching materials based interconnect integration. Thisresearch is a classroom action research by using a design developed by Kemmis and McTaggart. The model consists of three stages, namely the planning stage, the stage oftreatment and observation, and reflection stages. The results of this study show that teachingmaterials based interconnect integration has succeeded in improving students' criticalthinking skills of a score of 23 on the pre-action stage, 27.7 in cycle 1, and 36.6 in the secondcycle.