Abstract: Defated wheat germ protein flour (DWGPF) is a good plant protein resource. Its functionality should be studied thoroughly and put into a good use. The effects of pH (4.0～8.4), incubation temperature (20～70 ℃) and time (10～30 min) on water retention (WR) and protein solubility (PS) of defatted wheat germ protein flour were studied with the method of homogeneous design. WR increases apparently with the increase of temperature from 20 ℃ to 70 ℃. The effects of pH and time are noticeable and trace respectively. Maximum WR occurs at 70 ℃ and pH 4.0. The pH influences PS apparently, but incubation time almost doesn't do it. The highest PS was at pH 8.0 and 20 ℃. The experiment results also indicate that DWGPF, as an additive, can improve nutrition and quality of food.