The　concept　of　parity-time　(PT)　symmetry　originates　from　the　framework　of　quantum　mechanics,　where　if　the　Hamiltonian　operator　satisfies　the　commutation　relation　with　the　parity　and　time　operators,　it　shows　real　energy　spectrum.　Recently,　PT　symmetry　was　introduced　into　various　systems,　such　as　optics,　electronic　circuits,　acoustics,　and　other　classical　fields　to　further　study　the　dynamical　behaviors　of　the　Hamiltonian　and　the　energies.　To　focus　on　the　dynamical　evolution　of　the　quantum　state,　here　we　experimentally　studied　the　dynamical　evolution　of　a　two-level　quantum　system　under　the　PT　symmetric　Hamiltonian　using　single-photon　system.　By　enlarging　the　system　using　ancillary　qubit　and　encoding　the　subsystem　under　the　non-Hermitian　Hamiltonian　with　post-selection,　the　evolution　of　the　state　can　be　characterized　with　a　high　fidelity.　Owing　to　the　effectively　operation　of　the　dilation　method,　our　work　provides　a　route　for　further　exploiting　the　exotic　properties　of　PT　symmetric　Hamiltonian　for　quantum　simulation　and　quantum　information　processing.　©　2020　Optical　Society　of　America　under　the　terms　of　the　OSA　Open　Access　Publishing　Agreement.