The samples of some typical alkyd resins with various oil lengths and formula-tions，which are the products in different stages of esterification during the manufac-ture of alkyd resin，were characterized by HPGPC，VPO，wet analysis，Gardner’s tube viscosity and high temperature viscosity． It has been shown that the increase of Mw is much faster than that of Mn and the MWD broaben graduately．The Mn Value predicated in theory is larger than that mea-sused by VPO．The nH of the high concentration solution of the alkyd resins at high temp．are correlated to the Mw by the Mark-Houwink equation．For the alkyd resin end-products，which was synthesized by the alcoholysis of vegetable oil，with various oil lengths and formulations

the order of polydispertive index d is as follow：short oil lengthw and d．