SiO_2micro-cantilever has been widely used in the field of chemical and biolo gical sensors due to its high sensitivity.In order to further improve the dynamic sensitivity of SiO_2micro -cantilevers,the fabrication and its sensor application based on higher resonance modes are studied in this work.First,Silicon-on-insulator (SOI) is used as starting material for the fabrication of T-shaped SiO_2micro-ca ntilevers with different lengths.Then,commercial atom force microscopy (AFM) wit h accurate photoelectron ic system is employed for the characterization of the frequency and the frequency shift before and after mass adsorption.It is found that the first three bending frequencies of the T-shaped SiO_2micro-cantilevers with total length of 250μm are 18.86kHz,164.27kHz and 467.25kHz,respectively,which are well consistent with the simulated values.More over,for the same amount of mass change,the higher the flexural resonance mode is,the larger the frequency shift of the micro-cantilever will be,showing an increasing sensitivity.The frequency measur ement of gold deposition reveals that the sensitivities of the first three modes are 1.36Hz/pg,9.78Hz/pg and 26.92Hz/pg,respectively.Immunological reactions are also conducted.It is found that at the second harmonic,a 21.5pg m ass absorption can be detected.