Fiber laser is widely used in many fields, such as optical fiber communication, optical fiber sensing, spectrum measurement and so on. A broadband continuous tunable erbium-doped fiber laser with multiple output ports is designed and fabricated based on a digital micromirror device (DMD) and widely tunable optical filter. The characteristics of the laser are theoretically simulated and analyzed using a traveling-wave rate-equation model. Based on the theoretical results, an experimental system of the broadband tunable fiber laser with eight output ports is built. The experimental results show that the output wavelength range for each output port is 50 nm, which covers the whole C band and extends to S and L bands. The pumping threshold power is 17 mW, the 3 dB linewidth of the output laser is less than 0.02 nm, and the side mode suppression ratio is greater than 50 dB in the whole band. The stability of the laser output is measured within 100 min. The results show that the power fluctuation is less than 0.4 dB, and the wavelength jitter is less than 0.02 nm.