Modal localization, owing to its high sensitivity to structural perturbations, has demonstrated unique advantages in the field of microelectromechanical systems (MEMS) sensors. However, traditional modal localization resonators mostly rely on frequency-swept excitation, which can only stimulate a single mode and suffer from poor amplitude stability in open-loop operation as well as instability issues in dual closed-loop driving. These limitations hinder the realization of real-time measurement and fast response. To address this challenge, this paper investigates a coupled double-beam resonator and proposes a modal localization sensing method based on broadband noise excitation. The proposed method drives multiple modes simultaneously using broadband noise and extracts the variation characteristics of the modal energy distribution through power spectral density analysis, enabling efficient and sensitive perturbation detection. A coupled dynamic model of a dual beam MEMS resonator under broadband noise excitation is established, and numerical simulations together with experimental studies are conducted to comparatively analyze the modal responses under frequency-swept and noise-driven excitations. The results show that the modal localization effect under broadband noise driven conditions is highly consistent with that under harmonic driving, thereby verifying the feasibility and effectiveness of the proposed method.