High-pressure technology for polyethylene production has been widely used by industries around the world. The high-pressure autoclave reactor model developed in this work is based on a non-isothermal dynamic model, where PID control equations are used to maintain the operation at the unstable steady state. Kinetic mechanisms to describe the polymerization rate and molecular weight averages are presented. The model is capable of computing temperature, concentration gradients and polymer characteristics. The model was validated using industrial data, presenting good representation of the behavior of the autoclave reactor. © 2006 Elsevier B.V. All rights reserved.21C639644Chan, W.M., Gloor, P.E., Hamielec, A.E., (1993) AIChE.J., 39, pp. 111-126Georgakis, C., Marini, L., (1982) ACS Symp.Ser., 196, pp. 591-602Hulburt, H.M., Katz, S., (1964) Chem. Eng. Sci., 19, p. 555Zabisky, R.C.M., Chan, W.M., Gloor, P.E., Hamielec, A.E., (1992) Polymer, 33, p. 2243