The hydrocarbon-generating potentials of residual ocean basin get more and more attention. Based on the fact that the Junggar basin is underlain by the Precambrian continental block, an upper Paleozoic residual ocean might exist in west Junggar and aast Kazakhstan named the Balkhash-West Junggar residual ocean. Bole-Ebinur Lake sag lies in the south margin of the basin. Many sets of source rocks composed of upper Devonian-lower Carboniferous mudstone, marlstone and biolithite limestone are discovered from Bole-Ebinur Lake sag in southwestern margin of basin. The average TOC of source rocks is 2.19%, and the maximum is 7.11%. And, more close to oil-soaked clastic rocks in Bole-Ebinur Lake sag, the saturated hydrocarbon of source rock extract shows bimodal distribution type with odd-carbon predominance. According to light-to-heavy carbon-number ratios and asphaltenes contents, the upper Paleozoic source rocks well-preserved in the basin are still in a medium mature stage with high hydrocarbon-generating potentials.