In design of an adaptive optics system, a critical consideration is the bandwidth requirements for turbulence-induced tilt compensation, Tyler frequency. A method to evaluate the Tyler frequency is proposed according to the measured total tilt power spectrum. First, the power spectrum of the horizontal turbulence is measured through a Shark-Hartmann wavefront sensor. Then, the Tyler frequency is determined by which the tilt cut-off residual error of a diffraction angle is applied. The result illustrates that the tilt power spectrum is proportional to f-2 (f is temporal frequency) at high frequencies. At last, the circadian variation of Tyler frequency is acquired. It illustrates the important fact that, at night and early morning, the Tyler frequency of horizontal turbulence changes slowly, generally less than 4Hz in the turbulence condition, but it is volatile during the day, the largest up to about 20 Hz in Changchun. Therefore, the temporal bandwidth of the tip-tilt, in which the adaptive optics systems are used for the horizontal turbulence correction under such turbulence condition, must exceed 20 Hz.