Interest in mindfulness and relationship satisfaction is increasingly growing. However, although partners in a relationship have mutually interacted, there are few studies exploring this from a dyadic perspective. Thus, this research aims to investigate this dyadic association and furthermore the mediating role of attachment-related process, attachment avoidance and anxiety via Actor-Partner Interdependence Model. Participants of the study were 196 heterosexual college student couples, 196 males' average age 21.26 (SD = 2.17), 196 females' average age 20.66 (SD = 1.88), relationship length ranging from 1 month to 95 months (M = 22.25 (24.67) for males, M = 20.98 (18.98) for females), approximately 36.73% of couples in long-distance love. They were measured by the Five Facet Mindfulness Questionnaire, a revised version of the Experience in Close Relationships Questionnaire and the Intimate Relationship Quality Questionnaire. Results showed that the actor effects of mindfulness on relationship satisfaction were significant for both males and females, while the partner effect only displayed for males. It revealed a mixed dyadic pattern for males and an actor-only pattern for females. Additionally, actor-partner interdependence mediation analysis showed that actor mindfulness was associated with higher relationship satisfaction directly and indirectly. Indirectly, higher actor level of mindfulness was linked to greater secure attachment, lower attachment avoidance, and attachment anxiety, and thus to higher relationship satisfaction. Partner mindfulness was associated with higher relationship satisfaction only indirectly in two ways. Higher partner levels of mindfulness were associated with secure attachment, lower partner avoidance, and self's attachment anxiety, and thus to self's higher relationship satisfaction. The current study advances our understanding of attachment in the association between mindfulness and relationship from a dyadic perspective. Limitations and future research were discussed.