This study aims to determine the construct validity of the instrument used in the application of Blended Learning. Respondents were randomly selected 60 students from the Department of Geography, Faculty of Mathematics and Natural Sciences, Makassar State University, 60 students from the Department of Biology Education, Faculty of Teacher Training and Education, Patompo University, and 60 students from the Department of Primary Teacher Education, Faculty of Teacher Training and Education, Megarezky University. Construct validity was tested by Confirmatory Factor Analysis (CFA) in Structural Equation Modeling (SEM) through the AMOS 22.0 application. The analysis findings reveal that the indicators employed in developing the Instrument for Blended Learning Model Application encompass the constructs of Orientation, Organization, Investigation, Presentation, Analysis, and Evaluation. These constructs meet the criteria of Construct Reliability, Variance Extracted, and Discriminant Validity. Consequently, the instrument proves suitable for implementation in research examining the application of the Blended Learning Model.