Toward advancing the understanding of day-to-day family dynamics, this study examined the transmission between marital and parent-child relationship qualities for both fathers and mothers with a daily diary method. The cross-person association (i.e., one parents' marital relationship and his/her spouse's relationship with the child) was tested in addition to the within-person association. Moreover, this study tested whether these daily links were different for families with a child of different ages and would change over three years. Participants included 237 families, in which both fathers and mothers completed daily diaries for 15 consecutive days each year for three years. At the end of each reporting day, parents independently rated their emotional quality with the spouse and the child on that day. Positive associations were consistently found for the within-person transmission of both mothers and fathers, supporting the spillover hypothesis. When the cross-person association was examined, evidence was found supporting the compensatory hypothesis for mothers: poorer average marital relationship quality of fathers was related to increased level of mothers' daily relationship quality with the child. Furthermore, weaker within-day spillover effect was found for families with older child, suggesting an age-related change of the relationship quality transmission. The longitudinal model corroborated the above finding by showing a decrease in mothers' daily relationship quality transmission over three years. The findings illustrated the interdependent, changing, and dynamic patterns of family relationships and underscored the importance of differentiating the father-child and mother-child relationship.