Abstract: In the past several decades,the marine origin of Paleozoic oil and gas in China has long been an important problem to which petroleum geologists pay great attention.A major breakthrough was made in 1984 when well Shacan 2 encountered Paleozoic oil of marine origin in the Tarim basin,which for the first time demonstrates that "the Paleozoic marine deposits in China contain abundant oil".However,how are the prospects of Paleozoic marine oil and gas in China? Some people think that they are a key strategic substitute area for petroleum exploration,while others consider that they have no broad prospects but are only an auxiliary area for petroleum prospects.From the great advances in Paleozoic petroleum exploration in the past decade,Paleozoic petroleum potentials,favorable tectonic conditions,association of multi-epochal petroleum and wide exploration areas,the author proposes that Paleozoic marine oil and gas in China has great exploration prospects and will be one of the important strategic substitute areas of petroleum exploration in China.