The purpose of this study was to determine the aspects of critical thinking in implementing a blended learning-based project model in improving learning outcomes by utilizing digital applications and platforms. The research subjects were 20 students who were interviewed and filled out a questionnaire. Based on the hypothesis, it is revealed that there is a positive impact of critical thinking aspects on learning outcomes. These aspects include interpretation, analysis, evaluation, inference, explanation, and self-regulation. Data were collected through observation, interviews and documentation. This type of research is development research (R&D) with the concept of Thiagarajan 4D theory (Define, Design, Develop, and Disseminate). Data were analyzed using descriptive statistics and qualitative analysis. With the findings: the results of statistical analysis for the critical thinking aspects studied, all aspects influence on student learning outcomes. Based on the six aspects, the highest influence is the interpretation aspect of 82% on student learning outcomes.