This paper develops a two-echelon inventory model with time-weighted partial backorders. The presented model assumed to follow continuous review (Q. r) policy for both the retailers and the central warehouse under stochastic demand. A heuristic method to find an optimum-tending solution for total variable system cost per year incurred at the central warehouse and retailers in a system is suggested. To show the usefulness of the above model, numericla examples are illustrated for verification and validation purpose.