In this report, we mainly focus on the dynamic of the transient thermal effect of the C70/toluene at nanosecond
time-domain. We use the time-resolved pump-probe system based on 4f coherent imaging system with phase object with
nanosecond laser pulse at the wavelength of 532nm.By changing the delay time, we can get different linear and nonlinear
image. So the dynamic process of the transient thermal can be studied. In the experiment, we choose 5ns, 8ns and 10ns,
and found the nonlinear refractive index arises by the delay time.