The invention discloses a method for smelting reduction production and quenching and tempering treatment of rare earth and niobium containing mixed slag. The method comprises the steps that (1) a reducing agent, a niobium and rare earth containing material and/or an iron containing material are added into the rare earth and niobium containing mixed slag to form mixed slag, the mixed slag is heated to be in a smelted state, smelting reduction is carried out, oxidizing gas is blown, and the temperature range of the mixed slag and the specific value and temperature of alkaline CaO/SiO2 are controlled in the process; and (2) separating and recycling are carried out according to different reaction devices, components of rare earth, iron, niobium and phosphorus in the mixed slag, free calcium oxide and the like are efficiently recycled, solid rare earth, niobium and iron materials are treated in a large scale through the smelting reduction process, meanwhile, quenching and tempering of the slag are achieved, resources are efficiently and comprehensively utilized, and the method is a new smelting reduction ironmaking process. The method is short in reaction time, high in metal recycling rate, low in production cost, high in raw material adaptability, environment-friendly and high in economic benefit, and the aim of efficient recycling of multi-metal grandidierite metallurgy resources and heat energy can be effectively achieved.