Considering a supply chain consisting of a manufacturer，a retailer and a third-party B2B online spot market，we research the manufacturer’s optimal bidding strategy for options and the retailer’s optimal procurement strategy in a Stackelberg game with the manufacturer as the leader．In our model，we measure the liquidity of B2B online spot market by a parameter which means the probability of transaction success．We dis_x005fcuss two situations: manufacturer with adequate capacity and the manufacturer with limited capacity，and expand our conclusions to the special case of uniform distribution．Finally，we analyze the impacts of spot market liquidity on behaviors and profits of all participants in the supply chain through the numerical examples．