The postural instability and gait disorder dominant (PIGD) subtype refers to a subtype of Parkinson's disease (PD) with severe phenotypes, for which there is no effective pharmacological or surgical treatment. The clinical manifestations of patients with PIGD subtype are heterogeneous, which can be further complicated by other motor and non-motor symptoms of PD, severely affecting the quality of life of patients. Meanwhile, the pathogenesis of PIGD subtype remains unclear. This review dissects the heterogeneity of PIGD subtype in terms of symptom manifestations, contributing factors, pathological mechanisms and clinical treatment, aiming to provide a systematic and comprehensive understanding of the subtype.