In the manufacturing grid （MGrid） resource market, some resource service providers （RSPs） with resource information superiority tend to make a pooling equilibrium. Therefore, resource service demanders （RSDs） cannot evaluate resource quality owing to the imperfect information. In order to solve this problem, this paper proposes a resource trading approach of manufacturing grid based on the perfect Bayesian equilibrium. In this approach, with the support of MGrid system architecture, RSPs promise a compensation for the display of resource quality, thus achieving in separating equilibrium and preventing low-quality RSPs from sending out a higher compensation that high-quality RSPs would promise. Simulated results show that the proposed game model achieves a stable, reasonable and perfect Bayesian separating equilibrium, from which RSPs would not deviate initiatively.