This study attempts to identify the online test process of students with different proficiency and gender from the perspective of behavior, aiming to help teachers understand the valuable information about what the students hide behind their reading test behaviors and guide follow-up reading teaching strategies. The study records the students' test-taking behaviors in an online Chinese reading assessment system, and uses lag sequence analysis to explore and compare their behavioral patterns. The results show that the high proficiency students tend to quickly browse all the articles before the test and spend less time reading articles, but spend more time thinking when changing options. By contrast, the low proficiency students tend to read articles slowly as well as change options, suggesting their low confidence. The study also shows that girls use the mark function more often and tend to check the test before submitting it. In addition, compared with boys, girls spend more time on reading and answering the questions. These results demonstrate that girls pay more attentions than boys. Finally, this paper summaries the study limitations and provides suggestions for the future research and teacher teaching.