We report the application of saturable absorbers prepared from graphdiyne-modified tapered fibers to an erbium-doped fiber laser to achieve a femtosecond pulse output. Graphdiyne quantum dots are successfully prepared by the Glaser-Hay method. The graphdiyne-based all-fiber saturable absorber device exhibited strongly saturable absorption characteristics with a modulation depth of 18.06% and a saturation intensity of 103.5 W. The net dispersion of the erbium-doped fiber laser cavity is ~0.016 ps 2 , and a femtosecond pulse output with a bandwidth of 26.3 nm, a pulse width of 135.8 fs, and a single pulse capability of 54 pJ is obtained. This work lays the foundation for the application of the nonlinear optical material, graphdiyne, in ultrafast photonics.