The antilocalization effect is observed by magnetotransport measurement at low temperature on a Hg0.77Cd0.23 Te sample prepared by liquid epitaxy technique, which suggests a strong spin-orbit interaction within this system. The phase coherence time and spin-orbit scattering time of electrons are extracted by fitting the experiment data with the Hikami-Larkin-Nagaoka (HLN) theory plus the Drude conductance model. According to the temperature dependence of phase coherence time, we also find that the Nyquist mechanism dominates the dephasing process.