Based on slope IDT structure，Using 112°XY-LiNbO3 piezoelectric materials，by optimizing the group delay ripple design, apparatus aperture, dutycycle, IDT,the wavrlength of retroreflector and interdigital logarithm, a high performance SAW filter was achieved. The passband and the group delay time ripple is less than 0.2 dB and 22 ns, respectively. And the rectangular coefficient is less than 1.6. The proposed SAW filter has the features of flat passband, small group delay ripple, and high rectangular coefficient and good practicability.