SnO2/graphene quantum dots (GQDs) nano-composites were prepared via solvothermal method (160 degrees C, 10 h), in which graphene quantum dots were synthesized from graphene oxide by one-step solvothermal method. The nano-composites were characterized by means of HRTEM, XRD, SEM, FTIR, XPS and N-2 adsorption-desorption, respectively. The sensor devices were fabricated using SnO2/GQDs nano-composites as sensing materials. The effect of the GQDs content on the gas-sensing responses and the gas-sensing selectivity was investigated. The experimental results showed that the sensor based on SnO2/GQDs nano-composite (S-2) exhibited good response and good selectivity to acetone vapor. When operating at 275 degrees C, the responses of the sensor based on SnO2/GQDs nano-composite (S-2) to 1000 and 0.1 ppm acetone reached 120.6 and 1.3, respectively; the response time and the recovery time for 1000 ppm acetone were 17 and 13 s, respectively.