Like human speech,singing of songbirds is sensorimotor learning by tutor and auditory feedback. The development and crystallization of singing is depended on the integrity of the song system composed of vocal pathway and anterior forebrain pathway. X area in forebrain pathway plays an important role during learning and memory of singing. In this paper,we reviewed studies on the organization and the function in singing development and crystallization,the synaptic plasticity of X area. We also compared learning and memory function of X area to that of mammalian basal ganglia.