The objective of this study was to evaluate the efficiency of use of the Frechet function for modeling the diameter structure of eucalypt. We used data from permanent plot inventory, measured at ages 28, 40, 52, 64, 76 and 84 months. Set for every occasion and share with the function Frechet 3 and 2 parameters and using the location parameter of the stand as the minimum diameter (γ = dapmin). The function was fitted by maximum likelihood method. The adhesion function to the data was verified by applying the Kolmogorov-Smirnov (K-S. The construction of the diametric distribution model based on the correlation of the pdf parameters stand characteristics. All adjustments to the data presented adherence by K-S test.The equations that comprise the model of the diameter distribution of 2P and γ = dapmin showed no bias in their estimates, and may be used to describe the diameter distribution of even-aged stands.