Abstract: The boiling points and melting points of 15n-alkanes (carbon number 216) were predicted multiple linear regression based on the molecular structural parameters with molecular rotation model. The rotation inertia of molecular short axis are responsible for the boiling points(bp=-147·2-0·01189c+36·17nwithR=0·9985 andSD=6·97),buttherotational inertiainlongmolecularaxisandreorientation energy are responsible for thesawtoothbehaviorof melting pointsofn-alkanes. The multiple regressione-quation of four factors including rotational inertia in three dimensions and reorientation energy is successfully used to describe the melting points ofn-alkanes(withR=0·9999 andSD=1·07)