From the master equation of the field density for the two-photon process, with the help of the generation function method, the expressions of the squeezing of the square of the field amplitude generated in two-photon absorption process are derived. The variations of the square of the field amplitude with the dimensionless time τ, the phase θ and the average number of photons of the incident field are discussed. It is shown that the two-photon absorption process is an effective way generating the squeezing effect of the square amplitude of the field. Finally, the independence of the amplitude-squared squeezing effect is demonstrated.