In this paper, quantitative structure activity relationships (QSAR) of 20 compounds which belong to nucleoside analogue were studied by using the method of molecular connectivity index, and one equation of QSAR was established ( R =0 94). The model revealed that the anti HIV 1 activity was significantly correlated with the n M,lg P , (lg P ) 2 and 6 χ v P. As known from the equation, the molecular connectivity index 6χ v P played more important role than that of ...