In this paper, the extraction mechanism of free formaldehyde in the urea formaldehyde resin finished cotton fabric is discussed. An empirical equation for formaldehyde release has been formulated. $$F=3.7 imes10^{-3};H;T^{2.2326}+440$$ in which, F: the amount of free formaldehyde extracted ($mu$g/g) H: extraction time (min) T: extraction temperature ($^{circ}C$)