Autonomous learning ability is the basic ability of the talents to keep a foothold in the society. The educational concept of autonomous learning has become the common understanding of the educational circles. Based on metacognitive strategy theory, this study attempts to introduce task-based teaching method into college English teaching, and constructs a task-based teaching model of English autonomous learning based on metacognitive strategy theory. The method of contrastive analysis is used to analyze the teaching effect of this teaching model. The result shows that the task-based teaching model of English autonomous learning based on metacognitive strategy theory is conducive to stimulating students' intrinsic learning motivation, training and improving their cognitive level and metacognitive strategy, which can make full use of learning resources to effectively promote the cultivation of students' autonomous learning ability. This study provides a theoretical and practical basis for the promotion of college English teaching and the cultivation of students' autonomous learning ability.