When THz waves interact with different media,detector detects the THz time-domain waveform of carrying media information at different time nodes,the flight time difference between the THz pulses is analyzed,extraction model of transmission and reflection THz nondestructive inspection of single point thickness are established respectively. In flexible assembly process,refractive index of silicone adhesive is difficult to be extracted. Based on the single-point thickness extracting model,a three-dimensional topography of adhesive spatial distribution is drawn,and the standard deviation for thickness uniformity is put forward to evaluate the discreteness of adhesive spatial distribution. Analyzing the uniformity of adhesive thickness using THz-TDS system,the detecting accuracy is up to 100 μm,and it is important for ensuring the adhesive connection strength.