This paper analyzes the global chemical kinetics of CCA fixation process in the wood of Pinus elliottii and models the evolution of the process of setting function of time at different combinations of temperature and relative humidity. For this purpose, 2 cm cub specimens were impregnated by a vacuum-pressure process with CCA C solution (2% by mass) and were treated in climatic chamber according to nine combinations of temperature and relative humidity for seven days. The fixing process evaluation was carried out by means of the determination by UV-Vis spectrophotometry, the concentration of Cr (VI) leaching from treated wood sawdust with demineralized water. The main process speed CCA fixation is mainly controlled by the speed of the chemical reactions involved. An equation reliable rate law of the main stage of the process of CCA fixation on wood, which involves climate conditions and exposure time.