In order to realize a highly stable and tunable laser output,an Er3+-doped tunable fiber laser based on Mach-Zehnder filter structure and F-P filter is proposed. The theory of the laser was analyzed,and the feasibility was verified by the experiments. In the designed laser configuration,one 976 nm laser diode (LD) is used for pumping;an Er3+-doped fiber (EDF) of 5 m length is selected as the gain medium. A single longitudinal mode (SLM) laser output was realized based on all-fiber M-Z filter and F-P filter. In the experiment,when the pump power is 60 mW,a stable and tunable single wavelength tunable laser output with 1547~1568 nm is realized by adjusting the filter. The tunable spacing is less than 1.7 nm,and the side-mode suppression ratios (SMSRs) of each wavelength are more than 55 dB,and the line-width of the SLM output is less than 0.1 nm.