Contribution: This article illustrates a theoretical model and an analytical tool for understanding the influence of diverse elements of the project-based learning (PBL) environment on engineering identity development in students. Supportive elements in three dimensions that contribute to students' identities as future engineers are identified to inspire the improvement of future PBL design. Background: Prior research has investigated the components and impact factors of engineering identity, emphasizing the importance of understanding engineering identity development in diverse learning contexts. While a wide range of educational activities has been regarded as contextual factors that influence students' feelings about becoming engineers, it is still unclear what learning elements from the PBL context could contribute to engineering identity development in students, and limited analytical tools are developed from and tested in the PBL environment. Research Question: What elements of the PBL environment contribute to engineering identity development in students from the students' perspectives? Methodology: Considering the dimensions of internal motivation (IM), competence beliefs (CBs), and external support (ES), a survey was designed based on prior qualitative studies and conducted at a leading Danish university. The survey's content validity, construct validity, and reliability were tested using expert review, exploratory factor analysis (EFA), and Cronbach's alpha. Findings: Supportive PBL elements for engineering identity development in students were reported in the dimensions of IM, CBs, and ES. Among the three dimensions, IM was identified as the most important for allowing students to develop the feeling that they would become engineers in the future. Comparisons between genders, educational levels, and academic subjects verified the different impacts of the three dimensions on engineering identity development.