For the purpose of conformal array resolution performance, the signal model of conformal arrays(conical conformal array, cylindrical conformal array, spherical conformal array) are built in this paper, and polarization-DOA estimation is realized based on MUSIC, through the definition of MUSIC null spectrum and expectation of noise subspace projection matrix. The expectation of MUSIC spectrum and the resolution threshold of MUSIC for conformal array are derived in detail. The resolution threshold relationship between theory and simulation, conformal array and uniform circle array are studied by computer simulation. Simulation results show that resolution threshold of conformal array is reduced gradually with the increment of SNR, and the correctness of theoretical analysis is certificated by the simulation.