The invention provides a weaving, dyeing, sizing and washing processing oil-containing waste gas purification and waste heat comprehensive utilization system and method, and relates to the technical field of sizing and washing equipment of textile weaving and dyeing production lines. The weaving, dyeing, sizing and washing processing oil-containing waste gas purification and waste heat comprehensive utilization system comprises a heat exchanger, a sprayer, a dehumidification coil pipe, a white smoke eliminator, an electrostatic dust collector, a chimney, an oil skimmer and a refrigerator, the sprayer is connected with the dehumidification coil pipe, the dehumidification coil pipe is further connected with the white smoke eliminator, and the white smoke eliminator is connected with the electrostatic dust collector. The electrostatic dust collector is further connected with the chimney, the oil skimmer is connected with the sprayer and the white smoke eliminator, and one side of the refrigerator is connected with the heat exchanger. Through reasonable design of the oil-containing waste gas treatment system, the system is high in extraction rate of oil in the oil-containing waste gas and can prevent the phenomenon of explosion in the treatment process, safe machining is guaranteed, and a guarantee is provided for safety of workers.