Under the background of educational informatization, data-driven teaching decision-making has become a key means to improve the quality of education, but there are some shortcomings in the use of data in college English teaching decision-making. This study constructs an evaluation system of college English teaching decision-making ability, covering data awareness and literacy, data application ability, decision-making optimization ability, and collaborative innovation ability. Through the empirical study of two parallel classes of English majors in a university, the results show that the evaluation system can accurately identify learning problems, optimize teaching strategies, and improve students' language ability and classroom participation. However, the system has some shortcomings, such as difficulty in obtaining data, limitation of evaluation system, and teachers' excessive dependence on data. This study provides a path for improving the decision-making ability of college English teaching and also provides a way for the digital transformation of teaching.