The quality of English language instruction in the classroom is a pivotal factor influencing students’ learning outcomes and performance in English. Grounded in this research context, this study draws upon relevant theoretical frameworks and examines a cohort of 80 students from the 2023 English class at Anhui Medical College. A multiple regression model was constructed using various dimensions of classroom instruction—namely, content, methodology, organization, teacher competence, instructional attitude, and linguistic features—as independent variables, with students’ English achievements serving as the dependent variable. Utilizing SPSS statistical software, both multiple regression and principal component analyses were employed to investigate the correlations between classroom teaching practices and student performance. The main conclusions of the article after the test are: in the rating of English teaching classroom performance, the teacher’s teaching ability (5.0952) scores high, and the teaching method (3.0324) scores the lowest, and the teacher’s teaching ability has a close relationship with the students’ English achievement. English achievement = 2.136 + 0.223*Teaching content + 0.41*Teaching style + 0.129*Classroom organization + 0.227*Teaching competence + 0.189*Teaching attitude + 0.449Language characteristics. There is a need to improve the performance related to classroom teaching and thus improve the performance of students.