We presented an integrated silicon microring resonator based on slot waveguide f or biosensor applications.The index change of the analyte filled in the slot can make a shift in the resonance wavelength of the microring resonator.The device was designed by using Finite-Different Time-Domain method.Calculation results show that the effective index of the slot waveguide changes linearly with the in dex of the sensing material,which insure the effective optical sensing of biomol ecules.The device was fabricated on an SOI wafer with 220nm top silicon on a μ m buried oxide by using e lectron-beam lithography and inductively coupled plasma etching.The radius of t he microring is as smaller as 30μm.The light was vertically coupled in/out b y using waveguide grating couplers,and transformed from the rib waveguide to slo t waveguide by using a standard width taper.The quality factor of the slot micro ring resonator was measured to be as high as 2940.The spectra for bulk sensing were measured by flowing sodium chloride solutions with different concentrations on the surface of the s ensor.The resonance shift was analyzed by comparing the spectra.Experimental res ults show that the sensitivity and the LOD of the sen sor are 980.24nm/RIU and 5.4×10－4 RIU,respectively.