Abstract: A cislunar relay cooperative transmission scheme was proposed based on the Queqiao communication, navigation, and remote sensing satellite constellation system. To address unreliable data transmission in ultra-long-distance cislunar communication environments caused by highly dynamic channels and significant path loss, using the in-orbit information processing and multi-source data fusion capabilities of Queqiao communication, navigation and remote sensing satellite constellation system. By introducing a symbol-level forwarding strategy and a multi-source redundancy sharing mechanism, a distributed RaptorQ transmission mechanism for heterogeneous data fusion was designed, enhancing the reliability of image data transmission. By adopting a block-based cyclic decoding algorithm, the computational complexity was reduced by 40% compared to the standard Gaussian elimination decoding algorithm, while still ensuring strong error correction performance. Simulation results demonstrate that in typical cislunar space communication scenarios, compared to traditional RS coding, the proposed distributed RaptorQ scheme achieved a 2 dB coding gain under equivalent coding redundancy. Compared to conventional relay storage-and-forward schemes, this approach increased decoding success rate by 20%, thereby improving image PSNR by over 5 dB, enabling highly reliable transmission of multi-source image data in cislunar space.