Herein, we designed and constructed a model photocatalyst oxygen-deficient Bi@Bi2MoO6 (Bi-BMO-OVs) through a one-step solvothermal synthesis to deliberately regulate ROS generation and seek the crucial function of ROS during sodium pentachlorophenate (NaPCP) photochemical decomposition. The metallic Bi and oxygen vacancies (OVs) introduced in Bi2MoO6 prominently encouraged the yields of 1O2 and O2−, and synchronously blocked the formation of powerful OH. Unlike the nonselective performance of OH, 1O2 and O2− were experimentally and theoretically substantiated to account for the direct dichlorination and hydroxylated dichlorination respectively during photocatalytic NaPCP decomposition. With more O2− and 1O2 involved in the dechlorination process of NaPCP, easily decomposable quinone intermediates were produced, thereby realizing the rapid and efficient mineralization of NaPCP. This present work casts a new light on ROS mediated visible light photocatalytic decomposition of polychlorinated organic pollutants and opens up new possibilities for achieving their rapid detoxication via precise ROS regulation.