Running records is an important reading assessment for diagnosing early readers' needs in diverse instructional settings across grade levels. This study develops an innovative app to help teachers administer running records assessment and investigates teachers' perceptions of its functionality and usability in practical classrooms. The app offers unique features including multi-level running records assessments, student profile management, database support, and analysis of reading behavior patterns. Compared with paper-based running records assessment, not only can the app assist teachers in identifying the reading behaviors and the types of cuing systems a student has used, it may improve their teaching efficiency by discovering patterns of common errors and designing follow-up instructions. Teachers with prior knowledge of administering running records assessments were recruited to evaluate the app. The results indicate it is easy to use and teachers are willing to integrate it into their own instruction curriculum for reading assessment. The study concludes by summarizing contributions to the existing literature and making recommendations for future research.