A method for preparing a three-dimensional porous graphene-carbon nanotube electrode used for enzyme catalysis is provided. The method includes 1) a step of mixing a graphene oxide solution and carbonnanotubes under stirring, performing ultrasonic treatment for 1-2 h, adding the mixture into a reactor, reacting the mixture at 160-180 DEG C for 10-12 h to obtain hydrogel of a cylindric three-dimensional graphene-carbon nanotube composite, and freeze-drying the hydrogel to obtain a powdered three-dimensional porous composite; 2) a step of soaking the composite obtained in the step 1) into N,N-dimethylformamide, and performing ultrasonic treatment for 30-60 min to obtain a uniform dispersion; and 3) a step of covering a glassy carbon electrode with the dispersion. Compared with separate three-dimensional graphene, the three-dimensional porous graphene-carbon nanotube electrode is advantageous in that tube structure of the carbon nanotubes in the composite has good electrical conductivityand can increase the electron transmission rate. Compared with separate carbon nanotubes, the three-dimensional porous graphene-carbon nanotube electrode is advantageous in that a three-dimensional porous structure can provide more attachment sites for glucose oxidase.