We study possible CP-violation effects of the Higgs to Z-boson coupling at a future e+e- collider, e.g. the International Linear Collider (ILC). We find that the azimuthal angular distribution of the muon pair, produced by e+e- → H Z → H μ+ μ-, can be sensitive to such a CP-violation effect when we apply initial transversely polarized beams. Based on this angular distribution, we construct a CP sensitive asymmetry and obtain this asymmetry by Whizard simulation. By comparing the SM prediction with 2σ range of this asymmetry, we estimate the discovery limit of the CP-odd coupling in HZZ interaction.