Based on mycelial growth rate, the fungitoxicity of Acinetobacter baumannii against Botryosphaeria berengeriana de. Not.f. sp. Piricola (Nose) Koganecawa et. Sokwwwa was assessed and the field trial efficacy of pyrimethanil in controlling the pear perennial canker was evaluated. The results showed that the EC50 of Acinetobacter baumannii of crude product to pear perennial canker was 0.022 mg/L. And adding Mg2+, Ca2+, Mn2+ to pear perennial canker had significant synergy. The metal ions in the antibacterial synergism Ca2+ were significantly higher than Mg2+ and Mn2+, and Mg2+ was much higher than Mn2+. The efficacy of 226500 mg/L Acinetobacter baumannii was 74.56 %80.67 % and 69.51 %75.72 % for the pear perennial canker both in harvest time and in storage period, which was also safe to pear trees.