Terahertz communication, as an important research topic in the context of the next generation of large-capacity wireless networks, is of great significance to construct high-speed inter-satellite quantum communication networks. The inter-satellite terahertz continuous variable quantum key distribution scheme based on Gaussian-modulated coherent states usually uses active modulation to prepare quantum states, namely, amplitude and phase modulators and quantum random number generator are required. However, the implementation of high-speed active modulation with high extinction ratio and high stability are very challenging in practice. Besides, the modulation format of active modulation is relatively complex and can only tolerate small modulation errors, which are not conducive to the construction of high-speed inter satellite quantum communication networks. In view of the above analysis, this paper proposes an inter-satellite terahertz continuous variable quantum key distribution scheme based on passive state preparation, that is, the thermal terahertz source, beam splitter, optical attenuator and homodyne detector are used for passive modulation of quantum states. Therefore, it can eliminate the need for amplitude and phase modulators and quantum random number generator, which effectively simplifies the implementation of the inter-satellite terahertz continuous variable quantum key distribution protocol based on passive state preparation. This paper analyzes the security and performance of the inter-satellite terahertz continuous variable quantum key distribution protocol based on passive state preparation. The simulation results show that the performance of the proposed protocol is significantly improved with the increase of the average photon number of the thermal terahertz source and the frequency of the quantum signal, and getting closer to the performance of the ideal Gaussian-modulated intersatellite continuous variable quantum key distribution protocol. In addition, we present the schematic diagram of the local oscillator system for the proposed scheme and analyze the physical feasibility and practical technical approaches from a practical perspective, offering an effective pathway to constructing a low-cost and low-complexity inter-satellite quantum communication network.