No consensus has been reached on the depositional types in the 2nd sand group of middle Es3 Member in Fan162 and Fan3 Blocks of Daluhu Oilfield，Boxing Subsag. Based on cores，logging data，seismic data and analytical data，the sedimentary characteristics，sedimentary evolution and depositional model in the 2nd sand group of middle Es3 Member were systematically studied. The results show that hyperpycnal flows deposits in semideep-deep lake are regarded to mainly develop in the study area，and are characterized by：①wave cross-bedding and climbing ripples bedding formed by water flow；②a large amount of terrestrial material，such as black carbonaceous plant debris，reddish-brown mud boulder and layered mudstone；③a series of coarsening upward interval and fining upward interval always appear in pairs with inner erosion surface. The hyperpycnal flows are controlled by flood influx which transports sediments to the delta front in the Northern Luxi Uplift. Two-stage deposition caused by waxing and waning flows shows a depositional tendency from weak to strong and then to weak. The main body of hyperpycnal flow developed a lentoid filling model and the lofting facies subsided to form a set of rootless fine-grained sediments without homochronous channel in late deposition period. Based on comprehensive analysis of climate，topography，structure，etc.，the depositional model of“inner fan-middle fan-outer fan”was constructed.