The invention provides a method for shaping noise and a device, wherein speech signals s(n) are done with adaptive noise shaping treatment to obtain singles s1(n), the signals s1(n) are done with fixed noise shaping treatment to obtain signals u(n), and the signals u(n) are done with speech coding to form output signals of a coding end. The invention further provides a method for shaping noise and a device, wherein speech signals s(n) are done with the fixed noise shaping treatment to obtain signals s1'(n), the signals s1'(n) is done with the adaptive noise shaping treatment to obtain signalsu'(n), and the signals u'(n) is done with the speech coding to form the output signals of the coding end. Because the fixed noise shaping treatment and the adaptive noise shaping treatment are noise shaping treatment for the speech signals and do not relate to residual signals of the speech signals and a predictive filter, the speech signals which are shaped by noise can be coded and reduced without any changing on a recoding end.