In this paper we are concerned with the growth rate of blowup solution to the equation u(t)(x,t)-u(xx)(x,t)=u(p)(0,t), (x,t)is an element of(-l,l)x(0,T). Using self-similar solution technique and comparison method, we obtain the growth rate of blowup solution and observe that the boundary-layer phenomena occurs. (C) 1996 Academic Press, Inc.