In this study, we propose that by diminishing only the pitch of the innermost air-holes-ring of a HF1 photonic crystal fiber, both an effective mode area up to 100 μm2 at 1.55 μm wavelength and nearly zero dispersion of 0.2 ± 1 ps/(km·nm) within a spectrum range of 1.23–1.65 μm can be achieved simultaneously. Because only one parameter is needed to be tuned in the proposed design scheme, the fiber would be easier to be fabricated compared to other fibers using either multiple changing parameters or additional kinds of materials and would have potential applications in optical communications.