The gray market has widely existed in many industries. Due to the lack of after-sales service and commodity reputation of gray products， consumers tend to be more sensitive to product price， and more cautious about product quality when buying gray products. Most of them will take the authorized product price in the high price market as an important price reference point， which results in the reference price effect. In addition， information asymmetry in the supply chain will lead to differences in the acquisition of product quality information between manufacturers and consumers. Therefore， manufacturers often face the choice of disclosing or concealing product quality information. A gray market supply chain composed of a manufacturer and a distributor is taken as the research object. Considering the distributor participates in speculation and the consumers’ purchase intention in the gray market is affected by the reference price effect， the influences of product quality information asymmetry on the manufacturer's disclosure strategy choice and the pricing-decision making of the gray market supply chain are explored. Firstly， taking the symmetric quality information as the benchmark， a manufacturer-led Stackelberg game model is constructed. It is found there exists a threshold of the upper limit of consumers' valuation of low-priced products， below （not below） which the gray market exists （does not exist）and the system achieves an interior point （boundary） equilibrium. In the asymmetric information scenario， there exists a unique quality disclosure threshold in the presence or the absence of the gray market， which makes the manufacturer's expected profits equal when disclosing and concealing quality. The threshold is affected by the upper limit of low-priced product valuation and the strength of reference price effect. When the gray market exists， whether the manufacturer chooses disclosure or concealment strategy， the increase of the upper valuation limit of low-priced products and the strength of the reference price effect will inhibit the gray market speculation of distributors. Information asymmetry does not necessarily benefit the manufacturer. It may benefit the manufacturer， only if the manufacturer conceals quality information. The distributor's participation in the gray market speculation will have an adverse effect on the manufacturer when the manufacturer discloses the quality， and while the quality is concealed， whether the distributor participates in the gray market speculation has no effect on the manufacturer. Through numerical simulations， sensitivity analysis of equilibrium solutions is carried out to reference price effect intensity in the case of information symmetry， and manufacturer's quality disclosure strategy and pricing decision under asymmetric information are analyzed. Then， the impacts of quality information asymmetry and distributors' participation in gray market speculation on manufacturer's profit are analyzed. The conclusions of this paper provide theoretical references for exploring the impacts of the quality information asymmetry and the reference price effect on pricing decisions of gray market supply chains， and the choice of manufacturer's disclosure strategy.