The invention relates to a method for preparing a pure hyaluronic acid nano fiber membrane. The method is that hyaluronic acid powder is dissolved in mixed solvent formed by water, formic acid and DMF to prepare solution, the solution is statically placed in ultrasonic wave for one hour to enable all bubbles to be precipitated to obtain transparent hyaluronic acid solution; and the prepared hyaluronic acid electrostatic spinning solution is added into an injection pump, spinning voltage, distance between a spinning nozzle and a collecting plate and flow of the spinning solution sprayed by the spinning nozzle are properly adjusted, and electrostatic spinning is conducted within 5-60 DEG C to spin the solution on a folding fan-shaped aluminum foil to obtain the hyaluronic acid nano fiber non-woven fabric with average fiber diameter of 200-600nm. The preparation process and the post-treatment process are simple, the hyaluronic acid nano fiber non-woven fabric can be obtained within the wide temperature range and the diameter distribution of the obtained hyaluronic acid nano fiber is even.