The demand for detecting minute mass in biology and chemistry promotes the research of high sensitivity and strong robustness mass sensor based on MEMS resonators in the past few decades. The nonlinear behaviors are introduced to improve sensitivity, frequency stability, resolution, etc. However, the bifurcation configuration will become sophisticated due to mechanical, electrostatic, and damping nonlinearities. In this paper, the nonlinear bifurcation behaviors in parametrically excited mode-localized resonators are theoretically analyzed and introduced to improve the robustness of mass sensors. The nonlinear dynamics is computed by using the method of multiple scales, which is validated by the harmonic balance method combined with the asymptotic numerical method. Then, the rules for controlling the two different bifurcation topologies are proposed. Notably, the sensitivity near the pitchfork bifurcation point can be enhanced by three orders of magnitude, and meanwhile, the sensor performs excellent antijamming ability to a specific damping range, which opens the way to avoid the problem of lack of robustness for bifurcation-based mass sensors.