The invention discloses a preparation method of cobaltosic-
oxide nitrogen-
doped graphene synthesized by 
laser and with adjustable 
oxygen vacancies. The preparation method comprises the following stepsof: using oxidized 
graphene to ultrasonically disperse in absolute ethyl 
alcohol, preparing into 0.33mg / ml suspension, taking 24ml suspension, adding 1.2ml 0.2M 
cobaltous acetate solution, 0.5ml NH4OH solution with the concentration of 30% and 0.7ml deionized water, and carrying out oil 
bathing for 10 hours at a temperature of 80 DEG C; pouring the solution into a reaction kettle, and reacting for 3 hours at a temperature of 150 DEG C; then carrying out high-speed 
centrifugation at a speed of 12000-20000r / m, then repeatedly cleaning for 3-4 times by using the deionized water, obtaining precipitates and carrying out freezing and 
drying; mixing a sample and the deionized water into a 
test tube according to the 
mass ratio of 1:2-1:5, and under magnetic stirring, using 15-97mJ energy of 
nanosecond parallel pulse 
laser to irradiate the solution for 5-25 minutes; carrying out centrifuging, freezing and 
drying to obtain the cobaltosic-
oxide nitrogen-
doped graphene with the adjustable oxygenvacancy. The preparation method disclosed by the invention has the beneficial effects that by adjustment for the 
irradiation energy and time of low-energy 
laser, the concentration of the 
oxygen vacancies in the composite 
system is adjusted and the unchanged structure of the composite 
system is maintained.