The invention relates to a method and a device for directly recovering the oxalate precipitate of waste acid. The method is characterized in that a soluble metal salt solution and oxalic acid are added in a precipitation-distillation kettle and sufficiently mixed to generate an oxalate precipitate and waste acid, and then the waste acid in the precipitation-distillation kettle is distilled and recovered; and water is added in the precipitation-distillation kettle, the oxalate precipitate is stirred into slurry, and then the slurry is discharged, filtered, washed and dried to obtain an oxalate product. The method can not only greatly reduce the evaporation capacity of waste acid as well as the energy loss and material damage in the prior precipitation process, but also greatly save the consumption of oxalic acid. In addition, the adopted device has the advantages of long service life, low maintenance cost, energy conservation and the like. The method and the device have the characteristics of simple process, less consumption of chemical raw materials, high efficiency, energy conservation, environmental protection and low running cost, and not only solve the problems of waste acid recovery and environmental pollution in the oxalate precipitation process, but also realize better economic benefit.