Abstract: With more oil & gas producing regions becoming mature, increasing decommission has turned into the global problem for oil companies.Except for some developed countries, governments are lack of clear regulations of decommission.There are a lot of uncertainties in the decommission process.An analysis of the existing oil contract model and its impacts will improve the legislations and regulations of decommission and avoid the risks associated with decommission for oil companies.Based on the analysis of international oil contracts, decommission is divided into four payment patterns.Different payment patterns have different effects on the cash flow, asset purchase, government tax and decommission supervision.Comparatively, the pattern of decommission supervision can better balance the interests between governments and investors, which may become the future trend of world decommission policy.