Emulsified fuel was produced by mixing bio-oil pyrolyzed corn stalk with commercial No.0 diesel oil as well as surfactants using a homogenizer. The performances of bio-oil/diesel oil emulsified fuels with two different bio-oil/diesel oil ratios were tested on a ZS1110 diesel engine. The load characteristic curves of the diesel engine were determined. The experimental results showed that the effective thermal efficiency of two kinds of emulsified fuel was higher than that of the pure No.0 diesel oil. For emulsified fuel at bio-oil concentration of 15%, the specific fuel consumption was lower than that of No.0 diesel oil. However, there was often carbon deposition surrounding the diesel injector nozzle when using emulsified fuel.