With the increasingly deep studies in physics and technology, the behavior of fractional oscillators have become the focus of scientific research. In this paper, the stochastic resonance (SR) mechanism of the overdamped fractional oscillator subject to multiplicative dichotomous noise is extensively investigated. Using the Shapiro–Loginov formula and the Laplace transformation technique, the exact expression for complex susceptibility is obtained. Resorting to numerical simulations, the SR phenomenon of the overdamped fractional oscillator is studied. Especially, the frequency of the external periodic force that induces multiresonance.