A plastic extrusion process control method includes: receiving a plurality of historical process data of a plastic extrusion process from a database, in which each of the historical process data includes a plurality of critical parameters and a plurality of quality value; dividing each of the critical parameters into a plurality of levels; grouping the historical process data according to the levels of the critical parameters to obtain a plurality of parameter sets; calculating a quality indicator of each of the parameter sets to build an empirical response surface according to the historical process data corresponding to the parameter sets; and configuring the critical parameters of the plastic extrusion process to an automatic manufacturing system according to the empirical response surface, such that the automatic manufacturing system performs the plastic extrusion process according to the critical parameters.