The invention discloses a self generated gas foam oil-displacing agent liquid and an application and injection increase and yield increase method thereof. The self generated gas foam oil-displacing agent liquid comprises a gas generation agent liquid and a gas release agent liquid, wherein the volume ratio of the gas generation agent liquid to the gas release agent liquid is 1:(1-1.2); the gas generation agent liquid is a 8-15% carbonate or bicarbonate solution; the gas release agent liquid is a solution comprising 6-12% inorganic acid, a 0.5-2% foaming agent, a 1-3% corrosion inhibitor and a 0.1-1% stabilizer. By adopting the self generated gas foam oil-displacing agent liquid, the pressure of a water injection well can be reduced, moreover, a water absorption profile can be improved, and the oil-displacing effect can be further improved.