The invention discloses a preparation method of a porous cobalt titanate microrod and rGO composite gas-sensitive material with a hexagonal-prism shape. The preparation method comprises the followingsteps of uniformly dispersing graphene oxide into N-methylpyrrolidone, so as to obtain an N-methylpyrrolidone solution of the graphene oxide; dissolving Co(CH3COO)2.4H2O and Ti(OC4H9)4 in ethylene glycol, uniformly agitating at a room temperature, and regulating a pH (potential of Hydrogen) value to 4 to 6, so as to obtain a light pink solution; adding the N-methylpyrrolidone solution of the graphene oxide into the light pink solution, uniformly agitating at the room temperature, and carrying out ultrasonic treatment; carrying out a microwave hydrothermal reaction, and then calcining, so as toobtain the porous CoTiO3 microrod/rGO composite gas-sensitive material. The method has high controllability to a component and morphology of the composite material; the operation is time-saving; cobalt titanate in a product is a porous CoTiO3 microrod; the microstructure demand of the gas-sensitive material is met, and proven through an experiment, the composite material is sensitive to ethanol gas, and moreover, has a lower working temperature.