As a defining feature of diagnostic assessment,diagnostic feedback serves as the vehicle through which diagnostic assessment guides and supports language learning.This study investigated students'use of UDig diagnostic feedback on reading in college English classroom.At the beginning of a semester,the student participants took the UDig reading test and were given diagnostic feedback.They were then interviewed for their perceptions of UDig diagnostic feedback.A 14-week longitudinal study was then carried out to document how the participants utilized UDig diagnostic feedback throughout the semester.In general,the participants expressed positive views of UDig diagnostic feedback and integrated the feedback into their learning process,which in return,exerted positive influences over their learning.This study has implications for how learning-oriented assessment tools can be implemented in EFL teaching in China.