Abstract: There are two series of earthquake event deposits in Dachenling formation of early Cambrian in Peilingjiao area, the West of Zhejiang Province. Which caused soft sedimentary deformation, on the first phase of earthquake, deposits are 240m thickness, and deposits are 320cm thickness on the second phase of earthquake. There are about 165cm thickness dolomitic limestone stratum with liquefied veins caused by earthquake on the second layer. The authors collected 14 samples of dolomitic limestone with liquefied veins. For evey sample, the authors analyzed C、O isotopic in vein material and surrounding rock（dolomitic limestone）respectively. The carbon isotopes(δ13CPDB-v) values of veins material, from -0.07 to -1.51‰. and theδ13CPDB-d values of dolomitic limestone of surrounding rock rang from +0.01 to-1.09‰. The test data belongs to normal marine carbonate rocks. But all of the test result shows that δ13CPDB-d＞δ13CPDB-v. It is because water-escape structure create isotope fractionation by earthquake , the later alteration and 12C prior to 13C remove from deposits during sluicing. Seismic action can cause the value of 13C occur negative drifts. The δ18OPDB-d value varies from -13.47 to -18.56‰ in the veins material and surrounding rock（dolomitic limestone）, and the δ18OPDB-d value varies from -12.65 to -18.09‰. That is because water-escape structure is a weak structure plane, easier to be influenced by atmospheric precipitation, and later hydrothermal alteration.

Key words: Seismic events, Carbon isotopes, Oxygen isotopes, Liquefied vein