The invention discloses a petroleum drilling waste water processing system and a method for processing petroleum drilling waste water. The petroleum drilling waste water processing system comprises a storage tank, a filter, a charge pump, an evaporation device and a concentrate circulating pump, the storage tank is used for precipitating the drilling waste water, the filter is communicated to an inner chamber of the storage tank through a pipeline and is used for filtering granular impurity in the drilling waste water, the charge pump is connected to the filter through the pipeline and is used for extracting the drilling waste water in the storage tank, the evaporation device is connected to the charge pump through the pipeline and is used for performing evaporative concentration to the drilling waste water, the concentrate circulating pump is connected to the evaporation device through the pipeline and is used for extracting a concentrate in the evaporation device, and the concentrate circulating pump is connected to the storage tank through the pipeline and is used for injecting the concentrate in the storage tank for storage. According to the invention, the system is used for processing the petroleum drilling waste water, can realize evaporation of the drilling waste water under condition that electric energy consumption is little, and can avoid atmosphere pollution and underground water pollution due to direct evaporation of sewage in current sunning pools.