The invention discloses a porous filter membrane material for purifying a waste salt solution and a preparation method of the porous filter membrane material. The preparation method comprises the following steps: using a block polyether amide copolymer as a raw material, dissolving the raw material in an organic solvent so as to prepare a stock solution of a casting solution, adding deionized water to the stock solution of the casting solution so as to form a mixed solution, performing low pressure defoaming on the mixed solution so as to prepare the casting solution, coating the casting solution on non-woven fabric, putting the coated non-woven fabric in an oven, and after full evaporation of the organic solvent, putting the obtained non-woven fabric into pure water for solidification andfilm formation so as to obtain the block polyether amide porous filter membrane material. The invention provides a preparation process of the porous water treatment filter material, organic impurities and coke impurities in the waste salt solution can be treated effectively through the prepared film material, and the preparation method has wide sources of raw materials, low raw material price, asimple process flow and easy industrialization.