Based on comprehensive analysis of cuttings debris, logging, outcrop observation and laboratory data, etc, a research is made on the sedimentary characteristics and the hydrocarbon generation capacity of Chang 1. The analysis of depositional evidences suggests that Chang 1 area of Upper Triassic Yanchang Formation contains sediments of deep-water lacustrine dark shale, oil shale and turbidites. The lake was caused by an abrupt transgression over depositions of anastomosing river. The widespread Chang 1 lacustrine rocks may have great significance to the information of Chang 2 and Jurassic reservoir in Ordos Basin.