Based on the mode selective coupler (MSC) in a cavity, a Q-switched pulsed erbium-doped fiber laser with switchable output modes is reported in this work. Through the joint action of the Bragg grating and MSC, the output wavelength selection and the conversion between different modes are realized. Because the MSC has mode separation characteristics and the laser cavity has a dual-branch output configuration, the laser output can be switched between different modes by adjusting the cavity loss. The dual wavelength Q-switched pulse output with linear polarization modes (LP01 mode and LP11 mode) is successfully observed. The laser with switchable output modes can be used in communication, particle trapping, and other fields.