In the grid resource market, there is a severe information asymmetry problem between the resource providers and the resource consumers. It leads to dishonest trades and results in the great loss of the resource consumers. We propose two mechanisms named reputation-aware aggregate mechanism and reputation-aware double auction mechanism to solve this problem: a resource provider?s reputation value reflects the reliability of its resources; our mechanisms decide the trades between resource providers and consumers in terms of both reputation and price. The simulation results show that the reputation-aware aggregate mechanism and the reputation-aware double auction mechanism can both obviously decrease the loss of the resource consumers. The latter is more flexible and it reflects the traders? wish better than the former at the expense of slightly reducing the honest deal times. They are efficient methods to solve the information asymmetry problem.