A way of fabricating a small-core index-guiding photonic crystal fiber (PCF) is introduced. The first ring of the air holes around the core is deformed, the shape of which is similar to the grapefruit, and the diameter of the core is 1.7 μm; the pitch and diameter of the air hole are 3.4 μm and 2.8 μm, respectively. Because of the special structure of the fiber, the effective refractive indices, dispersion coefficients of the fundamental modes, effective areas and nonlinear coefficients of the fiber are calculated by finite element method from 200 nm to 1600 nm. The results show that, in this wavelength range, the nonlinear coefficients of this fiber are extremely high and dispersion coefficients are positive. These characteristics are of benefit to the supercontinuum generating. After measuring the dispersion and loss properties of the fiber, the laser operating wavelength in 800 nm is chosen to be the light source because the loss in this wavelength is lower and the central wavelength of the pulse is in the range of abnormal dispersion. The femtosecond pulses with different powers are coupled into this small-core index-guiding photonic crystal fiber. The supercontinuum generating in the fiber is detected and analyzed.