Oil-gas reservoirs of marine strata in South China had undergone several evolution processes in the Caledonian, Indosinian and Yanshanian respectively, which induced oil-gas reservoirs to be reconstructed greatly by tectonic activity. The preservation conditions are destroyed badly and effective technique is absent in evaluating hydrocarbon preservation. Through studying chemical and dynamical rules of underground fluids, the damage degree and mode of reservoirs by denudation, fault-fracture and permeating downwards of meteoric water are analyzed from the dynamic and evolution view. Subsequently we try to appraise the formation and preservation of oil and gas and probe into a technological system of hydrocarbon preservation aiming at marine strata in South China.