The associations between classroom environment and students' outcomes are one of the heated topics in western classroom environment research． The study is a mixed method research． It analyzes the associations between senior high school students ’perceptions and their outcomes using Middle School English Classroom Environment Inventory ( MSECEI) developed by the author ，as well as interviews and observations． The study indicates : 1) There are distinguished gender differences in students ’perceptions of classroom environment and learning attitudes towards English ; 2) Classroom environment ，a major factor which influences students' outcomes ，predicts students ’learning attitudes and academic achievements with statistical significance ，and the learning attitude is the mediator between students ’perceptions of classroom environment and academic achievement ; 3) Task orientation scale can predict learner outcomes with highly positive statistical significance compared with other scales．