Since airframe noise gradually plays a key role on civil aircraft noise reduction, airfoil noise, which is a typical source of aerodynamic noise, must be paid attention to in further noise reduction in civil aircraft industry in the future. The trailing edge discrete noise at low and medium Reynolds numbers has characteristics such as ‘ladder’ frequency speed relationship, laminar flow requirements, and dipole noise. Its noise mechanism is concerned with stability theory and feedback loop. Although the appearance and intensity of trailing edge noise have been extensively studied, the research on the spatial distribution of trailing edge noise is still insufficient. Based on wavelet coefficients and CLEAN-SC algorithm, a two-dimensional planar microphone array was applied to analyze the trailing edge noise in the time-frequency domain. The experiment was carried out in the Beihang D5 aeroacoustics wind tunnel. The closed experimental section composed of Kevlar cloth was used to conduct noise research on the NACA0012 airfoil with a chord length of 300 mm. Through the phenomenon of intensity maintenance in the fixed frequency range found in the experiment, the position of the sound source intensity in the space and time domain corresponding to the wavelet analysis disassembled intermittently moves, which further confirms the more complicated mechanism that may exist in the feedback loop.