In big data environment, retailers who contact with consumers (customers) closely control the resources of customer big data and have rights to deal with these data,especially in supply chain with strong channel dependence. The pressure on manufacturers to acquire the customer knowledge from these data is increasing, and it is difficult to encourage retailers effectively to share the customer knowledge with the ordinary transaction contracts used in the past. Therefore, referring to the idea of equity incentive and introducing equity incentive variable, this paper designs a kind of equity incentive mechanism for customer knowledge sharing from the manufacturer's point of view, to enhance the incentive to retailers. The research shows that the equity incentive mechanism designed by a manufacturer could impel a retailer to improve its efforts for sharing customer knowledge. If the manufacturer's own customer knowledge innovation capability is high, the proportion of equity allocation to the retailer would be on the high side, which also would be happen if the retailer has low effort level for sharing customer knowledge. With the increase of equity share, the retailer's expected utility would increase, while the manufacturer's expected utility would increase before it reaches the maximum value and then decreases. Therefore, manufacturers need to control the threshold of share. Equity incentive mechanism strengthens the benefit sharing and risk sharing, further impels customer knowledge sharing and collaborative innovation between manufactures and retailers, which result to revenue increase of the both.