A MEMS based PZT film transducer array has been designed and fabricated to verify the feasibility of miniaturization of the emitter in the audio directional loudspeaker through researching the parameters of the directivity of micro audio directional transducer array in this work.The effects of the radius, quantities and space of the array elements on the directivity have been analyzed theoretically.The results indicate that the elements should be arranged in a square to realize the expected cylindrical sound beam and more elements can result in better performance of directivity.When the spacing between two elements are approximate to a half of wavelength, the amplitude of the side lobes are suppressed most effectively. In the end,the directivity characteristic of the MEMS based micro array has been tested and the experimental results are good with the theoretical results.