Abstract: In the normal conductive project of high beam in density proton linac in accelerator driven energy system, the high energy section uses side coupled cavity linac(CCL)structure,its frequency is 700 MHz, and operates on π/2 mode. CCL section accelerates the 30 mA, 80 MeV proton beam from the coupled cavity drift tube linac(CCDTL) to 1 GeV. The total length of CCL is 1 064 m, the focusing lattice is FODO, the focusing period is 8βλ. Bore radii of the cavities are 2.00, 2.25 and 2.50 cm, respectively. The cavities are optimized with SUPERFISH code. The calculation results of the cavities and energy gain are presented.