The invention relates to a waste water treatment system of ultraviolet light and ozone micro/nanobubbles, which comprises a raw water lifting pump, a reaction tank, an ultraviolet lamp casing pipe group, a micro/nanobubble generator and an ozone generator. The water inlet of the reaction tank is positioned at the upper part of the water inlet end of the reaction tank; a water outlet overflow weir is arranged at the upper part of the water outlet end of the reaction tank; the ultraviolet lamp casing pipe group is hung on an upper cover of the reaction tank; the water outlet overflow weir is respectively communicated with a water outlet valve of the reaction tank and the water inlet of the micro/nanobubble generator; the air inlet of the micro/nanobubble generator is connected with the ozone generator; and the micro/nanobubble generator leads produced air-water mixture into the reaction tank. The waste water treatment system adopts ultraviolet light and ozone micro/nanobubbles, improves the mass transfer performance of ozone, greatly improves the utilization rate of ozone, and reduces the output of tail gas. The particle size of ozone micro/nanobubble is small, the quantity of the ozone micro/nanobubbles is large, the retention time of the ozone micro/nanobubbles is long, and the ozone micro/nanobubbles can scrub the surface of an ultraviolet lamp casing pipe while being spread in water to prevent the adhesion or scaling of organic or inorganic pollutant.