Mass detection sensitivity and measuring accuracy of resonant mass sensors are mainly dependent on the analyte position, the resonant frequency, and the effective mass of the cantilever. For measuring concentrated masses or particles, a novel mass sensor incorporating V-shaped cross section cantilever was proposed by locating the analyte at predefined positions for both improving the mass detecting sensitivity and reducing the measuring deviation. The theoretical model for analyzing the mass detection sensitivity was established. With the same geometric dimension, the proposed sensor's sensitivities obtained theoretically and experimentally are 6.75×104 and 6.34×104 Hz/g, which are nearly 2.20 times as great as that of the custom made cantilever with a rectangular cross section. Thus, the feasibility of the proposed sensitivity improving method was adequately validated.