Based on the principle of the photoelectron angular distribution imaging spectrometry,the photoelectron image is investigated by using single-photon resonance and three-photo ionization. The physics sense of the angular distribution of the photoelectron is analyzed. The impact of the photoelectron interference effect in the process of multi-channel ionization on imaging spectrometry is emphasized,the relation between the information of the atomic states and the photoelectron angular distributions is discussed in detail.