The invention relates to one-dimensional CAN zeolite with an adjustable length-diameter ratio and a preparation method of the one-dimensional CAN zeolite. The length-diameter ratio of the one-dimensional CAN zeolite is 4-300. The preparation method comprises the following steps: 1) preparing acid-activated palygorskite; 2) preparing a precursor, dissolving aluminum nitrate into water at a room temperature, adding sodium hydroxide, fully stirring, adding the acid-activated palygorskite, and stirring evenly to form the precursor; and 3) preparing the one-dimensional CAN zeolite, namely stirring the precursor at the room temperature for 7-15 hours, reacting in a reaction kettle at 160-200 DEG C for 24-120 hours, washing and drying with deionized water to prepare the one-dimensional CAN zeolite with the adjustable length-diameter ratio. According to the method disclosed by the invention, no organic additive is added; the method is simple in synthesis step, low in production cost; and the synthesized crystal is adjustable in length-diameter ratio, high in crystallization degree and uniform in particles.