Recently, technology-supported formative assessment has caught researchers' increasing attention. Most of the relevant studies have been carried out in experimental situations to demonstrate the effectiveness of technology-supported formative assessment for learning. However, little is still known about how technology-supported formative assessment is viewed and experienced by teachers in their classrooms. To fill this gap, this study investigated teachers' voices and practices when they used a formative assessment multimedia learning environment (FAMLE) in their classrooms during three semesters, which involved continuous platform refinement. The findings show that the teachers encountered a number of problems in four major aspects, namely students' engagement, assessment task design, feedback and follow-up issues. FAMLE went through corresponding refinement in two rounds. A change was evident in teachers' pedagogical practice of FAMLE from summative and revision use, diagnostic use, to integrative use.