Abstract: A Hamiltonian of threemode system was derived based on secondorder nonlinearity. Using this Hamiltonian and conventional nonHermitian Hamiltonian method, we obtained the optimal analytical conditions for unconventional photon blockade under the condition of dual mode drive. And then, by solving the steady state solution of the master equation and secondorder correlation function, we obtained the numerical solution for unconventional photon blockade.

Key words: antibunching, photon statistics, unconventional photon blockade