Abstract: With the continuous growth of data transmission rate， 6G wireless communication system needs to use new spectrum resources. Terahertz band has great advantages in the future wireless communication field because of its high bandwidth and high speed. On the other hand， in order to meet the global coverage requirements of future wireless communication network， 6G wireless communication network needs to integrate ground wireless communication network and space communication network. In this paper， the deterministic channel model of terahertz inter satellite communication link is studied by using ray tracing theory. Due to the high frequency of terahertz， the influence of surface roughness was considered in the reflection and scattering rays of the model，and the Doppler shift was considered for the high dynamic of inter-satellite communication link. Based on the model， the key channel parameters of 1 THz carrier frequency， including received power， rices K factor， delay spread and angle spread， were analyzed in the intra-orbit and inter-orbit inter-satellite link scenarios.