Abstract: The Jiufotang Formation in the Qianhe Oil Field, Ludong depression, Liaoning is built up of a succession of submarine fan deposits generated by the gravity flows and tractional currents during the deposition of the Jiufotang Formation and Shahai Formation. Three sedimentary microfacies have been distinguished, according to lithologic associations and well logs, including the proximal fan, mid-fan front and terminal fan, of which the mid-fan front sandstones turned out to be excellent reservoir rocks because of the discovery of the industrial oil run indicated by the L1 well in the study area.