Preparation method of flexible porous carbon fiber

The invention relates to a preparation method of a flexible porous carbon fiber. The method comprises the following steps that plant cellulose lines with the diameter of 0.1-2000 micrometers are thoroughly cleaned and dried; 2, the plant cellulose lines processed in the step 1 are subjected to heat treatment at 700-1500 DEG C for 1-300 min in the reducing atmosphere, and therefore the flexible porous carbon fiber is obtained. No catalyst or solvent needs to be used, the method is easy to implement and suitable for large-scale continuous production, and the obtained flexible porous carbon fiber has the good flexibility and can be bent by 360 degrees; the internal structure of the flexible porous carbon fiber has the quite high degree of graphitization, a large number of crystal lattice fringes can be seen under high resolution, and the specific surface area is quite high and can reach up to 1362 m /g.