Transformer fault detection technology research has always been a hot topic in the field of transformer research. The transformer diagnostic technology based on audible sound is a newer transformer fault diagnosis method, which audible data acquisition process is a very critical step. So the performance of the audible acoustic signal acquisition device directly affects the determination of the diagnosis result. This paper analyzes and compares the structure and performance parameters of commonly used moving coil microphones, capacitive microphones and electret condenser microphones. According to the characteristics of the audible signal of the transformer and the detection requirement, it is recommended to use the electret condenser microphone in the audible diagnosis of the transformer. Finally, an electret condenser CRY333 microphone is used to collect the data in a certain area. The results show that the performance of the microphone is suitable for transformer audible acquisition.