To alleviate gain narrowing, the interference filter and the quartz birefringent filter were used to shape the spectrum of ultra-short pulse with the FWHM bandwidth of 13 nm at λ = 1053 nm. The parameters of quartz plate were decided by simulation with computer. The experimental result is coincident with the simulation of the spectrum shaping. The shape of the spectrum becomes flat at its top and the FWHM bandwidth broadens 2 nm.