In order to provide customers with a better shopping experience, many retailers have introduced the buy online and pick up in store (BOPS) shopping channel, so that the limited offline inventory is faced with multiple channels demand. Whether the introduction of BOPS channel is beneficial to retailers and how to fully utilize offline limited inventory is still lacking research. This study considers a retailer and two customer segments: physical store customers who purchase goods only through physical stores, and omnichannel customers who choose among various channels strategically. Most existing omnichannel research assume that retailers’ offline inventory satisfies offline channels with priority. This paper takes three service strategies into consideration, including store customer priority strategy(SPS), omnichannel customer priority strategy(OPS), and equal priority strategy(EPS). Compared with the traditional literature, it is found that the introduction of BOPS is not entirely beneficial to the retailer. The density of physical store (determining the customer’s store visiting cost) and distribution center (determining the customer’s online waiting cost) affect the retailer’s revenue. Moreover, it is found that if customers’ online waiting costs are low, and store visit costs are even lower, the introduction of BOPS channels with SPS and EPS can increase the retailer’s profits, while simultaneously increasing the consumer surplus for both store customers and omnichannel customers.