In the Jimsar sag, petroleum exploration mainly focuses on unconventional oil reservoirs. In recent years, breakthroughs have been made in multiple strata above and below the source rocks of the Lucaogou formation and across the sag, revealing its good exploration potential and the characteristics of a whole petroleum system. Based on seismic, drilling, logging, and organic geochemistry data, the formation conditions of the whole petroleum system, and the hydrocarbon accumulation model are investigated by thoroughly dissecting known oil reservoirs. The results show that there is an orderly symbiosis between conventional and unconventional reservoirs in the Jimsar sag. Horizontally, shale oil, tight oil, and conventional sandy conglomerate oil reservoirs are developed successively from the sag area through the slope area to the structural high. Vertically, tight oil, shale oil, and conventional oil reservoirs are found successively in the Jingjingzigou formation-Lucaogou formation-Wutonggou formation sequence. The source rocks of Lucaogou formation undergone mass hydrocarbon generation and expulsion in low maturity stage, laying a material foundation for the whole petroleum system. The Lucaogou formation contains sandstone/conglomerate, mixed-rock, and shale reservoirs successively from basin margin to basin interior horizontally, and full grain sequence reservoirs of overlying Wutonggou formation and underlying Jingjingzigou formation are found vertically. A three-dimensional hydrocarbon accumulation model consisting of three horizontal zones and three vertical floors is established. Controlled by the hydrocarbon generation evolution of source rocks of the Lucaogou formation and the presence of multi-type reservoirs, the Permian strata in the Jimsar sag show characteristics of a whole petroleum system with orderly symbiosis between unconventional and conventional reservoirs. Based on the theory of the whole petroleum system and the exploration practice in the Jimsar sag, the Permian petroleum exploration in eastern Junggar Basin should focus on the sags such as Shishugou and Jinan, especially for finding tight oil and gas reservoirs in the slope or sub-source areas, structural-lithologic oil and gas reservoirs in the above-source fault-step belts and high structural positions, and shale oil reservoirs in the inner-source zones.