In this paper, the effect of environment factors on KGM molecular dimension was discussed, such as ultrasonic, enzyme, concentration and temperature. The KGM polarity, molecular weight (Mw) and conformation were analyzed by digital polarimeter and LLS. The result indicated that the polarity change influenced by temperature and ultrasonic accorded with linear function equation. Mw of KGM gradually decreased with ultrasonic time and concentration of enzyme increase. The concentration of KGM was lower, the effect was more obviously. The changes of KGM Mw also brought regular change of molecular conformation. All offers the reference to reliabletheoretical foundations on controlling KGM molecular dimension and industrial application in exploiting KGM potential function and activity.