Maternal-separation (MS) is an important model to study the effects of maternal care on infant neuronal development. It has been previously shown that MS contributes to not only structural changes of neurons in the infralimbic cortex but also to significant behavioral changes in adulthood. However, the underlying mechanism of the MS effect on neuronal circuits is not clearly understood. In this study, we studied the effects of MS on the function related to somatosensory cortex (SSC) and spine remodeling in the SSC. We found that MS mice showed hypersensitivity to somatosensory stimulation at post-natal 4, 8 and 12 weeks. MS enhanced the turnover of mushroom-type spines, leading to a decrease of the number of spines in the SSC in young and adult mice observed by using in vivo two-photon laser microscopy imaging. We conclude that MS during development affects the stability of dendritic mushroom spines in the SSC, which possibly produces impairment of the sensory behavior in adult mice.