In order to easily achieve phase matching between interacting waves in waveguide and generate effective second harmonics, a new type of strip waveguide silica-lithium niobate-silicon dioxide(SiO2-LiNbO3-SiO2) is designed. The strip wave-guide is composed of SiO2 and LiNbO3 without etching z cutting. The dispersion of the waveguide is analyzed by adjusting the waveguide structure, and the influence of SiO2 with different sizes on the phase matching points of the fundamental wave and the second harmonic is studied. The feasibility of frequency doubling of the strip waveguide is analyzed, and the ultra-wideband continuous spectrum is realized by using the characteristics of the amplitude and width of the pulse to broaden the spectrum. The simulation results show that an ultra-short pulse with a pulse amplitude of 107 a.u.and a pulse width of 10 fs is used to obtain an ultra-wideband continuous spectrum with a bandwidth of 1 302.5 nm in a strip waveguide structure with a covering layer SiO2 width of 1 600 nm and a height of 400 nm.