Let (M-n, g, e(-phi dv)) be a smooth metric measure space. In this paper, we derive a series of gradient estimates and a Harnack inequality for positive solutions of a nonlinear parabolic partial differential equation (Delta(phi) - partial derivative(t))u = qu + au(ln u)(alpha) in M-n x (-infinity,+infinity), where q is an element of C-2,C-1 (M-n x (-infinity,+infinity)) and a, a is an element of R. (C) 2019 Elsevier Ltd. All rights reserved.