Oxygen vacancies play a critical role in the sensing performances for metal oxides-based chemiresistor-type sensors. Developing facile and effective strategies for fabricating metal oxides with controllable oxygen vacancies is in great demand but remains paramount challenge. Herein, a novel organometallic chemistry-assisted method is reported to prepare SnO₂ samples containing controllable surface oxygen vacancies. This new approach combines modification of SnO₂ with dimethyltin dichloride, and subsequently thermal treatment in air atmosphere. Taking commercial SnO₂ as an example, it is found that the optimized SnO₂ sample possesses highest surface oxygen vacancy concentration of 37.13%. Owing to increased oxygen vacancy concentration, the resulting SnO₂ sample (SnO₂-Sn-0.5) presents excellent sensing performances for detection of acetone, including high response, fast response and recovery rate, good selectivity, compared with pristine SnO₂ with low oxygen vacancy concentration (28.66%). This work paves a new avenue for fabricating metal oxides with controllable oxygen vacancies for various applications of sensing, energy storage, and so on.