The optical properties of photonic crystal fiber cladding knot among the three air holes are analyzed. The mode area, nonlinear coefficient and dispersion characteristics of the core and cladding knot are contrasted. Cladding knot of photonic crystal fiber has a small core and highly nonlinear characteristics. For larger cladding air holes, double zero dispersion curves are obtained. According to the dispersion curve, phase-matching features are analyzed for dispersive wave generation. Variation rules of the central wavelength of the dispersive wave with pump power and wavelength are achieved. The photonic crystal fiber designed is fabricated. The visible and infrared broadband dispersive waves above 300 nm are obtained in experiment. Experimental and theoretical results are completely consistent with each other. These are foundation for wavelength conversion and supercontinuum broadband light source.