Correlation betweeiq the molecular structure of an explosive component and the combustion rate or rate-pressure index of a powder formulation is analyzed according to experience and preliminary results of combustion rate prediction research. It was found that low and high rate-pressure index powder differ greatly in the molecular structure of explosive component used and evident regularity exists. If this new concept and regularity are used as a principle to guide the molecular structure design or selection for a powder formulation,it will be possible to estimate the combustion properties of the formulation based on the characteristics of the chemical bonds of the components present,which will greatly benifit the formulation or combustion rate design and regulation.