///In this paper, the authors discussed the oil/gas geological features and the controlling factors of oil/gas accumulation in the Nanpu Ordovician buried hill based on core drilling, seismic and logging data. The results indicate that: 1) main kind of reservoir in the Nanpu Ordovician buried hill is fracture fissure-karstic composite reservoir; 2) high quality source rock in the 4 sub-member of Sha 3 member is the main source of oil and gas; 3) oil/gas reservoir distribution is controlled by predominant reservoir; in the crisscross transport system the longitudinal and transverse net which is composed of the faults and unconformities is the pathway of oil and gas migration; and 4) reservoir is the most important factor to control the oil and gas accumulation, so the main target of oil/gas exploration should be focused on the polycyclic tectonic-karstic controlled fracture fissure-karst composite traps in the Nanpu Ordovician buried hill.