With the wide employment of modern educational technology, college English teaching is going on a process of replacing traditional educational media with modern ones, which are closely connected with multimedia computers and internet technology to raise its efficiency and quality. However, some problems and challenges still exist in the college English teaching. In order to solve the problems, this article designs a test and collects data to check the effectiveness of the task-based approach within the Internet-assisted multimedia in college English teaching. The results show that Linguistic form was analyzed and practiced with task-based approach which may help the learners notice the linguistic problems and try out new language forms and structures, and that Internet-assisted multimedia has been effective in intriguing learners' interests and greatly enhanced their self-esteem.