A method for generating background noise, the method comprises: if an obtained signal frame is a noise frame, obtaining a high band noise encoding parameter from the noise frame; the high band noise encoding parameter includes a time envelope parameter and a frequency envelope parameter; performing weighting and/or smoothing on the high band noise encoding parameter to obtain a second high band noise encoding parameter; and generating a high band background noise signal according to the second high band noise encoding parameter; characterized in that, the performing weighting on the high band noise encoding parameter to obtain the second high band noise encoding parameter further comprises: multiplying the frequency envelope parameter with a preset weighting parameter to obtain a weighted frequency envelope parameter, wherein the weighting parameter is inversely proportional to the frequency value of the frequency envelope parameter; using the high band noise encoding parameter including the weighted frequency envelope parameter as the second high band noise encoding parameter; the performing smoothing on the high band noise encoding parameter to obtain the second high band noise encoding parameter further comprises: calculating with a preset first smoothing parameter and the high band noise encoding parameter to obtain the second high band noise encoding parameter according to a formula: P WB_LONG_SID = α ⁢ P WB_LONG_SID + 1 - α ⁢ P WB_SID wherein the P WB_LONG_SID is the second high band noise encoding parameter, α is the first smoothing parameter, and P WB _ SID is the current high band noise encoding parameter; if an obtained signal frame is a speech frame, obtaining a high band speech encoding parameter from the speech frame, and performing smoothing on the second high band noise encoding parameter according to the high band speech encoding parameter of the speech frame. if an obtained signal frame is a noise frame, obtaining a high band noise encoding parameter from the noise frame; the high band noise encoding parameter includes a time envelope parameter and a frequency envelope parameter; performing weighting and/or smoothing on the high band noise encoding parameter to obtain a second high band noise encoding parameter; and generating a high band background noise signal according to the second high band noise encoding parameter; characterized in that, the performing weighting on the high band noise encoding parameter to obtain the second high band noise encoding parameter further comprises: multiplying the frequency envelope parameter with a preset weighting parameter to obtain a weighted frequency envelope parameter, wherein the weighting parameter is inversely proportional to the frequency value of the frequency envelope parameter; using the high band noise encoding parameter including the weighted frequency envelope parameter as the second high band noise encoding parameter; the performing smoothing on the high band noise encoding parameter to obtain the second high band noise encoding parameter further comprises: calculating with a preset first smoothing parameter and the high band noise encoding parameter to obtain the second high band noise encoding parameter according to a formula: P WB_LONG_SID = α ⁢ P WB_LONG_SID + 1 - α ⁢ P WB_SID wherein the P WB_LONG_SID is the second high band noise encoding parameter, α is the first smoothing parameter, and P WB _ SID is the current high band noise encoding parameter; if an obtained signal frame is a speech frame, obtaining a high band speech encoding parameter from the speech frame, and performing smoothing on the second high band noise encoding parameter according to the high band speech encoding parameter of the speech frame. multiplying the frequency envelope parameter with a preset weighting parameter to obtain a weighted frequency envelope parameter, wherein the weighting parameter is inversely proportional to the frequency value of the frequency envelope parameter; using the high band noise encoding parameter including the weighted frequency envelope parameter as the second high band noise encoding parameter; the performing smoothing on the high band noise encoding parameter to obtain the second high band noise encoding parameter further comprises: calculating with a preset first smoothing parameter and the high band noise encoding parameter to obtain the second high band noise encoding parameter according to a formula: P WB_LONG_SID = α ⁢ P WB_LONG_SID + 1 - α ⁢ P WB_SID wherein the P WB_LONG_SID is the second high band noise encoding parameter, α is the first smoothing parameter, and P WB _ SID is the current high band noise encoding parameter; if an obtained signal frame is a speech frame, obtaining a high band speech encoding parameter from the speech frame, and performing smoothing on the second high band noise encoding parameter according to the high band speech encoding parameter of the speech frame. calculating with a preset first smoothing parameter and the high band noise encoding parameter to obtain the second high band noise encoding parameter according to a formula: P WB_LONG_SID = α ⁢ P WB_LONG_SID + 1 - α ⁢ P WB_SID wherein the P WB_LONG_SID is the second high band noise encoding parameter, α is the first smoothing parameter, and P WB _ SID is the current high band noise encoding parameter; if an obtained signal frame is a speech frame, obtaining a high band speech encoding parameter from the speech frame, and performing smoothing on the second high band noise encoding parameter according to the high band speech encoding parameter of the speech frame.