We propose and demonstrate a novel, to the best of our knowledge, scheme for atom interferometry along the direction deviating an angle from gravity, using slender light pulses that nest around a blue-detuned guiding optical potential (BDGOP). Cold atoms could be uniformly transported through guiding optical potential and interacted coherently by slender light pulses. We analyze the coherence of cold atoms in BDGOP using the Ramsey interference. In comparison to free-falling atom interferometry, the rapid exponential decay of fringe contrast is changed to slower linear decay when subjected to a tilting angle. The contrast could be enhanced approximately fourfold by BDGOP. Our work paves the way for inertial vector measurements based on BDGOP.