ZnO varistors with different amounts of ZnF2 from 0.00 to 0.80 mol% were prepared using a solid-state reaction technique, to explore the potential application of ZnO. The F-doping effects on the microstructure and electrical properties of ZnO-based varistors were investigated. The average grain size of ZnO increased from 4.93 to 6.48 μm as the ZnF2 content increased. Experimental results showed that as the ZnF2 content increased, the breakdown voltage decreased from 617 to 367 V/mm, and the nonlinear coefficient did not change much. However, a slight increase was observed in the leakage current. Besides, when the ZnF2 content increased, the donor concentration increased from 0.669 × 1018 to 8.720 × 1018 cm−3. The study indicated that ZnF2 played a similar role as sintering aids to promote grain growth and the substitutional F atoms in the bulk served as a donor to increase the donor concentration.