The aims of the study were to understand the pre-service science teachers' experiences about Algodoo Based STEM Education, to define views about it and, to emerge its influences on pre-service science teachers. Accordingly, case study method was utilized in the study. The participants were 30 pre-service science teachers who were fourth grade in a medium-size state university in Turkey. An intervention was performed to inform pre-service science teachers about Algodoo based STEM education during three weeks. The data were obtained from STEM activity plan, STEM activity plan evaluation rubric, and semi-structured interviews. Interviews were analysed through using descriptive and content analysis techniques together. Algodoo based STEM activity plans were examined by two researchers and evaluated according to the STEM activity plan evaluation rubric. According to the findings, pre-service teachers were planning to use Algodoo software in STEM activity mostly in elaborate stage and on physics topics. Although they have a few difficulties in using Algodoo software, they were aware of the contribution of Algodoo simulations to students, teachers and STEM education. Moreover, they mentioned the positive effects of this intervenion on them such as being happy, increasing motivation, providing professional development. The findings of the study are discussed in line with the related literature and suggestions were given.