A method for preparing a flexible thermoelectric thick film material with excellent electric transport performance by adding a sintering aid includes such steps as 1) uniformly mixing that thermoelectric material powder and the sintering aid to obtain a mixed powder, adding a sintering aid to the thermoelectric thick film material, adding a sintering aid to the thermoelectric thick film material,adding a sintering aid to the thermoelectric thick film material, and adding a sintering aid to the thermoelectric thick film material. 2) dissolving that polymer resin in an appropriate solvent to obtain a solution of the polymer resin; 3) uniformly mix that mixed powder and the polymer resin solution to prepare a thermoelectric slurry; 4) prin that thermoelectric paste onto a substrate by a printing method; 5) level that wet film of the slurry, drying and sinter. The invention has the advantages that the sintering aid is environmentally friendly and low in price, the electric transport performance of the flexible thermoelectric thick film material can be remarkably improved by adding the sintering aid, the preparation method of the thermoelectric thick film material is simple and controllable, the preparation period is short, the sintering aid is suitable for industrial production, and the development of the in-plane flexible thermoelectric device is expected to be promoted.