This paper details the radiation of laser induced air plasma. The plasma was produced by interacting the air with the Nd:YGA laser focused with optical lens. The relationship between spectrum of laser -induced air plasma at 1064nm and the laser power density was investigated, the time and space properties of the signal were studied, which provides a clear physical picture of laser induced air plasma. Results showed that the laser -induced air plasma has strong and directional radiation at 1064nm.