People has known that the recognition between cells and bacteria is related to the glycolipid, as a receptor on the cell surface. Diacetylene moiety in the hydrocarbon region can be cross linked by UV irradiation to form the corresponding polydiacetylene polymer. Color changes of polydiacetylenes have been known to occur in response to a variety of environmental perturbations such as heating, pH, mechanical stress or in the case of biosensor, due to the strong π π * absorption of the conjugation backbone. In this report, polydiacetylene mixed with mannopyranoside monolayer is prepared by Langmuir Blodgett film technology, E.coli K 12 adheres on the monolayer surface after gram strain. The result shows that the mannopyraoside could be recognitized by E.coli, but couldn’t be recognitized by O 111 B 4 and S.flexneri.