The invention discloses a method for realizing cross-layer optimization of satellite channel resources of a satellite network and relates to the technical field of optimization of the satellite channel resources. The method is based on a concept of distinguishing packet loss through a TCP-Casablanca protocol, discloses a cross-layer discrimination mechanism of channel bit error situations, self-adaptive variable marking intervals, a link error control mechanism and cross-layer sharing of modulation mode selection information aiming at the characteristics of transport layer acknowledgement (ACK), solves the problems that the traditional transmission control protocol (TCP) simply deems the causes of all packet losses as network congestion and congestion control strategies are taken blindly, can accurately distinguish the causes of the packet losses in the dynamically changed satellite network, proposes a reasonable link error control mechanism at the same time and therefore improves the throughput of the satellite network and the utilization ratio of the channel resources. The method has high flexibility and reliability and is suitable for high-bit-error-rate and high-delay satellite communication networks.