The invention provides a flat light frequency comb generation system based on a normal dispersion flat silicon nitride optical waveguide. The flat light frequency comb generation system based on the normal dispersion flat silicon nitride optical waveguide comprises an adjustable repetitive frequency pulse light source, a high-power EDFA light amplifier, an adjustable bandwidth light filter and a normal dispersion flat silicon nitride nonlinear optical waveguide; the adjustable repetitive frequency pulse light source is used as the pulse light source of the system; the repetitive frequency is 10-200 GHz adjustably; the pulse width is 1-2.5 ps; the light pulse is Fourier transform limiting light pulse; the high-power EDFA light amplifier is used for amplifying light pulse power; the adjustable bandwidth light filter is used for filtering the spectrum of a light signal, so that noise is removed; the normal dispersion flat silicon nitride nonlinear optical waveguide is used for realizing light frequency comb spectrum broadening and spectrum envelope flattening through self-phase modulation and optical wave breaking effect; and the nonlinear coefficient of the silicon nitride optical waveguide is 0.4-6 W<-1>m<-1>. The system provided by the invention can generate a coherent light frequency comb having continuous tunable frequency interval and better spectral envelope flatness.