A preparation method of a lanthanum-iron-loaded carbon nanotube film for environmental restoration is provided, it belongs to the technical field of composite materials. The preparation method includes: mixing carbon nanotubes with a lanthanum-iron mixed solution to obtain a suspension, then obtaining a first reaction solution by a constant temperature oscillation reaction; adding alkali liquor into the first reaction solution to obtain a second reaction solution by an oscillation reaction; carrying out a solid-liquid separation on the second reaction solution, adding the obtained solid after drying into an organic solution, and obtaining a third reaction solution by ultrasonic mixing; centrifuging the third reaction solution to obtain a supernatant; obtaining a lanthanum-iron-loaded carbon nanotube film by suction filtration. Compared with powdered adsorbent and single adsorbent, the material prepared by the preparation method has advantages of strong stability, high adsorption efficiency, good regeneration effect, high recycling efficiency, and low production.