Analysis of ZH recoil mass

The precise measurement of the Higgs mass is the most important program at International Linear Collider (ILC). Using e+e- -> ZH process, the mass of Higgs boson can be measured by two lepton tracks from decay of Z boson, even if the Higgs boson decays into invisible particles. We report the measurement accuracy on the Higgs recoil mass and the cross sections for ZH -> llX at sqrt{s}=250 GeV with the integrated luminosity of 250 fb-1.