Abstract: The Chao 84-6 well area was located in the intersection of the Tongyu-Baokang drainage system in the southwest and Changchun-Huaide drainage system in the south of the Songliao Basin during the deposition of the 4th member of the Cretaceous Quantou Formation in the Central depression, Songliao Basin. Due to complex convergence of multiple sources of the drainage systems, the sediment sources and palaeocurrent directions remain uncertain up to now. In the light of heavy mineral assemblages, ZTR indices and sandstone distribution, the authors in this paper contend that the sediment sources may be composed of the provenance I controlled by the Baokang drainage system in the southwest, provenance Ⅲ controlled by the Huaide drainage system in the south, and provenance Ⅱ controlled by the double drainage systems.