  We study the prospect of determining the CP violating phase in $\tau$-lepton
Yukawa coupling at the Large Hadron Collider (LHC). While the current run is
already exploring the production of a pair of the third generation $\tau$
leptons from Higgs decay, these measurements are not sensitive enough to
constrain the CP violating phase. In this paper, several CP odd observables are
proposed and analyzed utilizing the dominant channels with the semi-invisible
hadronic decay of $\tau$. Several asymmetries corresponding to the T odd
momentum correlations are also studied and their sensitivities to the CP
violating phase in tau-lepton Yukawa couplings are estimated at 13 TeV LHC with
1000 ${fb}^{-1}$ of integrated luminosity. We also present a novel way to
reconstruct $\tau$ momentum at the LHC utilizing the information of impact
parameter. Finally, we obtain that the asymmetries can be as large as 35$\%$
for a case of maximal CP violation in the $\tau$ Yukawa couplings.
