Dichlorophenoxyacetic (2,4 D) molecularly imprinted polymer was prepared with 2,4 D as temple molecule, α methylacrylic acid as functional monomer and methacrylic acid 2 hydroxyethyl ester as cross linker. The characteristics of the infrared spectrum of 2,4 D MIP was studied. The ability of recognition of 2,4 D MIP was tested by using flow stream potential measurement.