Abstract: In this paper,thegeneration and evolution models and primary migration features of biogases are mainly studied,and then the relations between their generation and migration are approached.The research indicates that biogases mainly have two inborn states and two migration patterns.The time of their large-scale migration is within their main gas-generating period.And their migration orientation is along the direction of buoyancy and residual pressure.They make short-distance migration from gas-generating centres to favorable traps nearby.