Abstract: Some characteristics of acoustic array antennas constructed with different horns are tested. The measured antenna directivity patterns are compared with theoretical patterns. The effects of wave length, distance between horns, the number of horns and the air temperature on directivity patterns are discussed. The measured directivity pattern of a 4×4 array basically agrees with the theoretical curve. The comparison of different types of horns shows that the piezoelectric ceramic tweeter has best conversion efficiency, which is three times of the common horn’s. The reflecting horn YH 5-4 has a good ratio of performance to price, and is suitable for phased array antenna manufacture.