Generation of squeezing light depends on the nonlinear optical processes. Its intensirv is usually low owing to the limitation of the conversion efficiency. In this paper, the general condition for producing squeezing light is given. According to this condition, the conclusion is obtained that a laser cavity with a nonlinear medium and a gain medium can sime-ltaneously amplify the light intensity and reduce the quantum fluctuation of one quadrature phase component of the light field.