Abstract: Symbiosis of oil and salt theory has been existed for a long time.It is estimated that 66 oil&gas basins develo- ping salt&gypsum rock have more than half proven re- serves in the world.With the characteristics such as strong plasticity,good fluidity,compactness and dehy- dration,the salt&gypsum rock is superior to other kinds of rocks and have the ability of generating,accumulating and sealing.In terms of hydrocarbon accumulation,this article makes a systematic discussion on the decisive role of salt&gypsum rock.It is found that the subtle hydro- carbon reservoirs are developed in salt interbed and lithol- ogy phase transformation zones.Moreover,it also points out the anhydrite layers are significant to geology in high- ly over pressured gas reservoir.