The pVT properties of linear alkanes are studied by molecular connectivity index and artificial neural network (ANN) . It is found that the properties can be directly calculated from the molecular structure. Here 25 compounds are treated as a training set to extract the weight factor by ANN. According to the training results of ANN
the pVT data of other 15 compounds were predicted. The calculated values are satisfactory. Using the ANN and the molecular connectivity index can provide a convenient and effective method to calculate the pVT data.