Under the background of showrooming effect consumers adopt theoffline experience and online shopping, which leads to the conflict of online andoffline channels. To alleviate the effect, the manufacturer designs the contractto incentive the retailer. The service quality cost contract and optimal dynamicquality decision are investigated. The result indicates that the goodwill, benefitsof members in centralized model are better than that in decentralized model.In decentralized model the service quality and goodwill are decreasing withthe increasing showrooming effect. The cost sharing contract can alleviate thenegative effect of showrooming effect on the goodwill. Finally, the contract canenhance the service quality of the retailer.