A modular fan blade includes a first fan blade and a second fan blade. The first fan blade includes a hub and plural first vanes, and the hub has an external periphery, and the first vane is combined with the external periphery, and a flange is formed at the external periphery and a retaining space is formed on a surface of the flange; and the second fan blade includes a fan frame and plural second vanes, and the fan frame is installed at the flange of the hub, sheathed on the hub, and installed in the retaining space, so as to achieve the effects of increasing the wind output of the fan effectively and replacing the blades conveniently.