Abstract: In the dual-channel supply chain, it is meaningful to develop reasonable promotion strategies to improve the profit of the upstream and downstream enterprises and reduce channel conflicts. Basing on the assumption that the channel demand is affected by the enterprises' dynamic promotion behavior, the product goodwill and consumers' heterogeneous channel preference, the dual-channel promotion problem between the manufacturer online and the retailer offline is studied, constructed the vertical joint promotion differential game models which were based on product goodwill and consumers' willingness to pay are constructed, explored the incentive effect of four models of non-cooperative, centralized, two-stage compensation contract and two-stage cost sharing contract on the promotion decision of channel members is explored, the influence mechanisms of buyer's countervailing force on channel members' promotional efforts and cooperative contracts is discussed, and the influences of consumers' channel preference and channel substitution parameter on enterprises' promotion decisions are analyzed.
The following conclusions are drawn from the study:①Under the influence of buyer's counterbalance force, the proportion of promotion cost sharing of upstream enterprises in the two-stage compensation contract has a double impact on the profit of upstream and downstream enterprises, this contract can motivate the retailers to reach the optimal promotion effort level which is achieved under the centralized decision-making, and also realize the Pareto improvement of the profit of the supply chain, but the incentive for manufacturers to promote are inadequate; ②The two-stage cost-sharing contract can motivate the enterprises of the upstream and downstream to promote at the same time, and ensure that the optimal promotion effort level equals to the situation under centralized decision-making, and no matter how the buyer's counterbalance forces change, it won't cause the decision deviation of the upstream and downstream enterprises, all the enterprises can realize the profit Pareto improvement after the transfer payment, and the supply chain can achieve perfect coordination; ③The influence of consumers' channel preference on the promotion efforts of upstream and downstream enterprises is determined by the marginal profit which is generated by channel preference.

Key words: dual-channel, promotion decision, mechanism of countervailing power, supply chain coordination