The rapid rise of information technology has popularized learning diagnostic systems in education, particularly in college English teaching. These systems boost teaching quality and enable precise instruction. This study delves into precision teaching in college English with two English major classes. Teaching experiments used data from the system to set goals, plan courses, choose strategies, assign tasks, and assess progress. SPSS analysis gauged the system's effectiveness. Results reveal enhanced student interest and performance in English with the system. The experimental group displayed heightened engagement and innovative learning methods, outperforming the control group significantly. Conversely, the control group struggled with traditional methods. The precision teaching model, aided by the diagnostic system, enhances English proficiency among college students, lending theoretical backing to its application in college English education.