We reported a pediatric case of Kawasaki disease complicated with mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) from Beijing Tsinghua Changgung Hospital. The clinical data were retrospectively analyzed and the related literature was reviewed. The clinical features, treatment and prognosis of the disease were summarized to improve recognition of Kawasaki disease complicated with MERS. A 7-year-old boy was diagnosed with Kawasaki disease due to continuous high fever for 6 d, accompanied by strawberry tongue, conjunctival congestion, erythema-like hyperemia rash, and cervical enlarged lymph nodes. And treatment was started with intravenous immunoglobulin (IVIG: 2 g/kg) and oral aspirin [40 mg/(kg·d)]. Twenty-four hours after the treatment of IVIG, the patient' s fever persisted and in addition he developed headache and drowsiness. His cranial magnetic resonance imaging (MRI) demonstrated a localized lesion in the splenium of the corpus callosum with high intensity signal on diffusion-weighted images (DWI) and T2-weighted, and low intensity signal on apparent diffusion coefficient (ADC) and T1-weighted. Based on these findings, he was diagnosed with MERS-complicated Kawasaki disease. Methylprednisolone [2 mg/(kg·d)] treatment was started intravenously, and within several hours he was afebrile and the neurological symptoms disappeared. A follow-up MRI was conducted after 1 week was normal. He was discharged without any neurological sequelae and coronary artery lesions. A total of 12 qualified foreign literature were retrieved, with no Chinese literature searched. Seventeen children were reported, the median age was 6.5 years (range: 1-14 years), among them 11 cases were children over 5 years old, and 4 cases were complicated with coronary artery lesions. All children had neurological symptoms, such as consciousness disorder, visual hallucination or convulsion. MRI conformed to MERS imaging changes. After active treatment, the neurological manifestations and radiological abnormalities completely disappeared, leaving no neurological sequelae. Kawasaki disease complicated with MERS had not been reported in China by now. Literature that identified Kawasaki disease complicated with MERS mostly occurred in children over 5 years old. Cranial MRI examination is helpful for early diagnosis. Timely treatment can reverse MERS in a short time, without neurological sequelae left.