Adolescent idiopathic scoliosis (AIS) is a spinal deformity involving 3 planes of the spine during adolescence. The pathogenesis of AIS is still unknown. Posterior spinal fusion (PSF) is the most widely used surgery in treating AIS. Its postoperative complications have gradually attracted attention. Deformity-related complications, such as adding-on phenomenon, proximal junctional kyphosis, distal junctional kyphosis, coronal imbalance and shoulder imbalance, are the most common ones. Understanding the definition, diagnostic criteria, incidence, natural history, risk factors, and preventive measures of these complications is essential to make surgical strategies for AIS. This article reviews the latest research on the deformity-related complications of PSF in patients with AIS.