This study proposes a modification of Chen and Liu’s (2008) model with a k-stage serial production system. Assume that the retailer’s order quantity is based on the manufacturer’s product quality, and that the quality characteristic of the product is normally distributed. The quality of a product lot for the manufacturer is determined by adopting a k-stage single sampling rectifying inspection plan. The used cost of customer for the product can be obtained by adopting Taguchi’s symmetric quadratic quality loss function. The modified economic manufacturing quantity (EMQ) model will be proposed for the manufacturer’s profit model. The optimal retailer’s order quantity and the manufacturer’s production run length and process mean will be jointly determined by maximizing the total expected profit of society including that of the retailer and manufacturer.