Searches for the Standard Model Higgs boson in the $H \to ZZ^{*} \to 4l$ decay with the ATLAS detector at LHC.

A strategy for the search of the Standard Model Higgs boson in the $H \to ZZ^{*} \to 4l$ decay channel with the ATLAS detector at the LHC is presented. The dependence of the analysis performance on the quality of data reconstruction and selection cuts is studied for the range of Higgs masses from 120 to 300 GeV. A particular emphasis is made on the procedure of separation of signal and background events. The influence of the Zbbbar and ttbar background channels on the selection of signal events is shown. The discovery potential of the Standard Model Higgs boson in the H->4l decay with the ATLAS detector is discussed.