The invention discloses a manufacturing method of flame-retardant rattans. The manufacturing method includes the following steps that (1) a log is sawed off and split, burrs on side edges of rattans are rubbed down, and the width of each rattan is 2-4 cm; (2) the rattans processed in the step (1) are put in the temperature of minus 25 DEG C to be subjected to quick freezing for 10-15 min, taken out and put in a flame-retardant solution at the temperature of 30-40 DEG C to be soaked for 12-24 h, and then put in a preservative solution at the temperature of 30-40 DEG C to be soaked for 12-24 h;(3) the rattans soaked in the step (2) are subjected to drying treatment, the drying temperature is 60 DEG C, heat preservation is carried out for 20-30 min till the water content is 30-40%, the temperature is reduced to 50 DEG C, heat preservation is carried out for 20-30 min till the water content is reduced to 10% or below, and drying is completed; and (4) the rattans treated in the step (3) are subjected to gum dipping, hot pressing treatment and then cold drying, the flame-retardant solution is evenly sprayed on the surfaces of the cold-dried rattans in a crossed mode, and the rattans areobtained after natural air drying. The rattans manufactured through the method are good in antiseptic and flame-retardant effect and harmless to the body.