The purpose of this study is to examine the relation between parental strain and marital adjustment of employed mothers after their transition to the parenthood, and to investigate buffering effect of social support on the relation. The parental strain variables (physical strain and emotional strain) appear to be significant predictors of marital adjustment for employed mothers with first baby. The analysis on interaction effect indicates that social support can be a positive buffering indicator. A comparison reveals that mothers with high physical strain have significantly higher marital adjustment than those with low strain. But in the context of high social support, the difference of marital adjustment between the two mothers is reduced.