The invention provides a method and a device for information sharing in a spatial information network. The method comprises the following steps that a current satellite obtains a current credit value of a target satellite; the current satellite judges whether the target satellite is reliable based on the credit value of the current satellite and the current credit value of the target satellite; if the target satellite is judged to be reliable, the current satellite carries out sharing negotiation with the target satellite; when a received sharing negotiation result which is fed back by the target satellite is to carry out sharing, the current satellite carries out physical layer information sharing with the target satellite; and after the current satellite carries out information sharing with the target satellite, the credit value of the current satellite is updated. According to the method, the propagation of the false physical layer information in a spatial network can be effectively prevented, the influence of the false physical layer information on the network is reduced, and a technical problem of larger probability of the false information which is provided when the information between the satellites is shared in the existing spatial network is alleviated.