Somnambulism is defined as a state of dissociated consciousness triggered by impaired arousal, which results in partial wakefulness and partial sleep. No effective therapy or medication has been available for treating children with somnambulism. Herein we present a case in a 4.5-year-old girl, who presented with somnambulism associated with separation anxiety disorder every night in a week. The girl received formal assessment and appropriate interventions, and the symptoms disappeared within a week. The treatment was carried out in 5 stages: diagnosis of the disease, establishment of trust, information collection, supervision, and individualized psychotherapy. Although dreams in childhood can be difficult to interpret, close observation of the behaviors in sleepwalking, as a special form of dream, in addition to the more precise description by the guardians, still provides useful clues to understand those dreams. For children with somnambulism, early intervention with psychotherapy can significantly decrease the false revival of the unconscious desires, and thus may serve as a treatment option other than medications.