Couple communication plays a crucial role in marriage life. Previous research mainly focused on the indicator of communication behavior to marital quality, less attention has been devoted to impact mechanism of the communication behavior on marital quality. Previous research indicated that attachment security were associated with couple communication, and also were associated with marital quality. The purpose of the present study was to explore the mechanism between couples’ observed communication behavior, attachment security and marital quality. To avoid shared covariance due to the methods, we used observational paradigm to catch couples communication behavior. The identified 41 newlyweds community couples were recruited by lab members, who contacted acquaintances to locate couples who met the eligibility criteria. Couples were visited in their homes by trained interviewers. After completing self-report measures, including Marriage Quality Index and Adult Attachment Scales, partners were reunited for four 10-min videotaped discussions, which including two problem solving tasks and two social support tasks. Iowa Family Interaction Rating Scale coding system was used to encoding couples interaction. The results revealed that couple’s positive behavior in problem solving can significantly positive predicted wives’ marital quality, and negative behavior in social support can significantly negative predicted husbands’ marital quality. Additionally, wives’ attachment security served to mediate the association between couple problem solving positive behavior and wife marital satisfaction, while the attachment security of husband didn’t play any role between couples’ communication behavior and husbands’ marital satisfaction. These findings suggested that communication behavior and attachment security have different impact mechanism on husbands and wives marital quality. And also, the present study was the first time to apply observational study paradigm in couple research, which open a new window for the methodology issue in this fields in China.