Given the impact of the global COVID-19 pandemic on children's schooling and learning, evidence for interventions implemented by parents is urgently needed. This study aimed to evaluate the effects of a parent-mediated LEGO intervention on the social interactions of four children on the autism spectrum in China. The intervention involved four sets of two parents engaging with their child in collaborative LEGO construction, with each person assigned a role as Engineer, Supplier, or Builder. Using a multiple probe design across the four family triads, the intervention effectively increased spontaneous social initiations and responses in all four children, and these behaviors were maintained for 6 weeks following the intervention. The effect on inappropriate interactions was not detected; parental prompts increased in initial intervention sessions but decreased over time. Parents implemented the intervention at home with high fidelity. Efficacy of the intervention and potential benefits of virtual parent training are discussed.