Educators believe that STEM activities allow students to use multiple skills to solve real-world problems; therefore, it has been recognized as an effective way to apply academic knowledge to life's problems. While many studies have examined the effectiveness and perceptions of students' learning through STEM activities, little research has been conducted on teachers' perceptions of STEM activities. In particular, there has been little research on teachers' preferences for STEM learning. Therefore, in this study, two questionnaires were employed to investigate the teachers' preferences for and perceptions of STEM learning and teaching. The questionnaire of teachers' preferences for STEM learning consisted of four scales, namely, activity flexibility, technology support, classroom interaction and teaching assistance, while the questionnaire of perceptions of STEM learning included higher order thinking, collaboration, and attitude toward STEM learning. A total of 307 teachers from 25 high schools in Taiwan filled in the questionnaire after conducting STEM activities. From the result of structural equation modeling it was found that teachers' perception of collaboration was the key element connecting the teachers' preference for STEM activities and attitude toward STEM learning. In addition, the teachers' preference for technical support and classroom interaction positively correlated with their perceptions of higher order thinking and collaboration, while activity flexibility and teaching assistance positively correlated with their attitude toward STEM learning. According to the results, it was found that teachers' perceptions of STEM learning were pluralistic and differed according to their preferences.