BiO1−xCl with optimum surface oxygen vacancies modulate the surface spatial electron structure and local electric field, and thus substantial photo-generated electrons were effectively ferry to the confined PMS by electron shuttles and hamper its random adsorption and disorder self-quenching. Ultimately, outstanding PMS utilization rate and pollutant removal rate was obtained. Display omitted •BiO1−xCl with optimum surface oxygen vacancies was prepared.•Surface oxygen vacancies confine activation PMS.•Surface oxygen vacancies halted the self-quenching of active species population.•Surface oxygen vacancies significantly boosted PMS utilization rate. Hinder self-quenching of active species and augment peroxymonosulfate (PMS) utilization rate is a challenging for advanced oxidation processes (AOPs). Therefore, BiO1−xCl with appropriate surface oxygen vacancies (SOVs) was fabricated by microwave reduction method. Experimental results reflect that BOC-2 can remediate 79.4 % doxycycline hydrochloride (50 mg L−1) in 1.75 h under the constantly yield active species population (ASP). Simultaneously, theoretical calculation discerns that reasonable SOVs can increase PMS adsorption energy, change PMS adsorption configuration and peroxy bond length. Thus, photo-induced electrons can fast ferry to the confined PMS via electron shuttles formed by SOVs to activate PMS. Ultimately, ASP self-quenching was halted and PMS utilization rate was ameliorated. Furthermore, the structure–activity relationship between SOVs and PMS utilization rate was established and the environmental toxicity of the intermediates was evaluated. This work offers an ingenious strategy to steer PMS activating behavior and boost its utilization rate by defect engineering.