The present invention relates to a nearshore subaqueous fan conglomerate sedimentation unit body division method. The nearshore subaqueous fan conglomerate sedimentary unit body division method under the erratic event gravity flow spin back sedimentation effect control is established, with the accurate division of a rift lake basin steep slope belt nearshore subaqueous fan conglomerate sedimentation unit body as an object, on the basis of the research of a nearshore subaqueous fan sedimentation cause mechanism and a sink sedimentation simulation experiment, nearshore subaqueous fan conglomerate sedimentation unit body division identification and classification standards are established, with the nearshore subaqueous fan conglomerate sedimentation unit body division classification standard as a guidance, the seismic data and drilling data division of a nearshore subaqueous fan sedimentation unit body is carried out, with the seismic data and drilling data division of the nearshore subaqueous fan sedimentation unit body as a basis, with single well time-depth relation as a constraint, the crosswell comparison of the nearshore subaqueous fan sedimentation unit body is developed, the accurate identification and division of the rift lake basin steep slope belt nearshore subaqueous fan conglomerate sedimentation unit body are carried out, the nearshore subaqueous fan conglomerate sedimentation unit body can be accurately and effectively divided, and the spatial distribution range is determined.