Abstract: The atmospheric turbulence's daily characteristic is concluded by a long term experimental study, which can be drawn as: the measured turbulence strength is usually week from 7 p.m. to 8 a.m. on the order of 10-15m-2/3, but it is always strong from 1 p.m. to 2 p.m. on the order of 10-13m-2/3. In addition, the test principle of instrument is analyzed. The relationship between turbulence strength and atmospheric temperature structure function and measurement precision is derived to evaluate the experimental result. This research provides fundamental data for atmospheric turbulence research on the optics wireless communication system.