We proposed and experimentally demonstrated a cascaded tilted fiber Bragg grating (TFBG) for enhanced refractive index sensing.The TFBG is UV-inscribed in series in ordinary single-mode fiber (SMF) and reduced-diameter SMF with the same tilt angle,and then excites two sets of superposed spectral combs of cladding modes.The cascaded TFBG with total length of 18 mm has a much wider wavelength range over 100 nm and narrower wavelength separation than that of a TFBG only in the SMF,enabling an enlarged range and a higher accuracy of refractive index measurement.The fabricated TFBG with the merits of enhanced sensing capability and temperature self-calibration presents great potentials in the biochemical sensing applications.