In order to efficiently monitor the selfish behavior in networks,form reliable relations and solve problems such as the single point of failure or bottleneck effect in traditional client-server environments,we adopt a novel P2P trust arithmetic named P-Trust based on the social people trust relation mechanism and the idea of IT governance,in which the direct trust arithmetic and the recommend trust arithmetic are modified.The P-Trust integrates the direct trust value and the recommended trust value to create the final trust value.Simulations prove that the P-Trust arithmetic can tackle the P2P trust problem in a simple and efficient way.