The situation of gasoline antiknock additives and the reasons of phenol type Mannich base as gasoline antiknock additives were discussed.Mannich bases were synthesized.The results of phenol type Mannich bases used as gasoline antiknock additives showed that these kinds of Mannich base compounds possessed good oil solubility and better antiknock ability.The RON of straight-run gasoline and 90# motor petrol with 5％(vol) of CPC112［2

4-di(dimethylaminomethyl)o-methylphenol］ could be increased by 9.7 units and 2.6 units . They had no corrosion on metal and they could be used as gasoline antiknock additives. Among all the studied Mannich bases，CPC112 had good prospect of application.