This research investigates the reconstruction of chargino pair with RPV decay to ττHH with special consideration on missing transverse energy. The leptonic-tau pair case is considered mainly. Since taudecay releases at least one neutrino (invisible to the detector) and all neutrinos released are in the same direction of the visible part, missing transverse energy (mET) can be used to improve the reconstruction of two tau cases. The mET vector is decomposed into the directions of the visible parts (leptons/hadronic tau jets) on the transverse plane and is then projected onto the real directions. An improvement of about 20% is achieved across energy levels from 250GeV to 1500GeV on truth level, and the reconstructed chargino mass peaks closer to the expected mass. This method also improves chargino mass distribution on reconstructed level, but the extra noise in reconstructed level may reduce the effectiveness.