Objective Investigating the effects of intraperitoneal EGCG administration on cerebellar Purkinje cell excitability and inhibitory synaptic activity in VPA induced autism spectrum disorder (ASD) mice, and its intervention efficacy on autism-like stereotyped behaviors and motor coordination/balance deficits. Methods Establish a VPA-induced ASD mouse model and administer intraperitoneal injections of EGCG (25 mg/kg and 50 mg/kg). Behavioral tests (marble burying, self-grooming, accelerating rotarod, and balance beam) are used to assess differences in repetitive stereotyped behaviors and motor coordination/balance among the normal control, VPA, VPA+25 mg/kg EGCG, and VPA+50 mg/kg EGCG groups. Electrophysiological recordings are performed to investigate alterations in both excitatory and inhibitory synaptic activity of cerebellar Purkinje cells across these groups. Results In the marble burying test and self-grooming test, 50 mg/kg EGCG intervention significantly alleviated repetitive stereotyped behaviors in VPA-induced ASD mice. In the accelerated rotarod test and balance beam test, 50 mg/kg EGCG intervention markedly improved motor coordination and balance abilities in VPA-induced ASD mice. Whole-cell patch-clamp recordings demonstrated that 50 mg/kg EGCG intervention effectively ameliorated the VPA-induced reductions in both excitability of cerebellar Purkinje cells and inhibitory synaptic activity in ASD mice. Conclusions EGCG dose-dependently modulated the altered excitability and inhibitory synaptic activity of cerebellar Purkinje cells in VPA-induced ASD mice, thereby ameliorating autistic-like stereotyped behaviors and motor coordination and balance impairments in VPA-induced ASD mice.