A frame loss compensation method for audio signals, comprising: after setting a frame type flag bit for each frame, by an encoding end, putting the frame type flag bit into a bit stream and transmitting the bit stream to a decoding end; wherein, setting a frame type flag bit for each frame comprises: for a frame with remaining bits after being encoded, calculating a spectral flatness of the frame, and judging whether a value of the spectral flatness is less than a first threshold K, if so, considering the frame as a multi-harmonic frame, and setting the frame type flag bit as a multi-harmonic type, and if not, considering the frame as a non-multi-harmonic frame, and setting the frame type flag bit as a non-multi-harmonic type; and for a frame without remaining bits after being encoded, not setting the frame type flag bit; the decoding end receiving the bit stream from the encoding end; when a first frame immediately following a correctly received frame is lost, the decoding end judging a frame type of the first frame which is lost, a first lost frame for short hereinafter, according to frame type flag bits set by the encoding end and received by the decoding end prior to the first lost frame and when the first lost frame is a non-multi-harmonic frame, calculating Modified Discrete Cosine Transform, MDCT, coefficients of the first lost frame by using MDCT coefficients of one or more frames prior to the first lost frame; the decoding end obtaining an initially compensated signal of the first lost frame according to the MDCT coefficients of the first lost frame; and the decoding end performing a first class of waveform adjustment on the initially compensated signal of the first lost frame to obtain an adjusted time-domain signal of the first lost frame; wherein, judging a frame type of a first lost frame according to the frame type flag bits set by the encoding end and received by the decoding end prior to the first lost frame comprises: acquiring a frame type flag of each of n frames prior to the first lost frame, and if a number of multi-harmonic frames in the prior n frames is larger than a second threshold n 0, wherein n and n 0 are integers and 0≤ n 0 ≤ n, n ≥ 1, considering the first lost frame as a multi-harmonic frame and setting the frame type flag as a multi-harmonic type; and if the number is not larger than the second threshold, considering the first lost frame as a non-multi-harmonic frame and setting the frame type flag as a non-multi-harmonic type. after setting a frame type flag bit for each frame, by an encoding end, putting the frame type flag bit into a bit stream and transmitting the bit stream to a decoding end; wherein, setting a frame type flag bit for each frame comprises: for a frame with remaining bits after being encoded, calculating a spectral flatness of the frame, and judging whether a value of the spectral flatness is less than a first threshold K, if so, considering the frame as a multi-harmonic frame, and setting the frame type flag bit as a multi-harmonic type, and if not, considering the frame as a non-multi-harmonic frame, and setting the frame type flag bit as a non-multi-harmonic type; and for a frame without remaining bits after being encoded, not setting the frame type flag bit; for a frame with remaining bits after being encoded, calculating a spectral flatness of the frame, and judging whether a value of the spectral flatness is less than a first threshold K, if so, considering the frame as a multi-harmonic frame, and setting the frame type flag bit as a multi-harmonic type, and if not, considering the frame as a non-multi-harmonic frame, and setting the frame type flag bit as a non-multi-harmonic type; and for a frame without remaining bits after being encoded, not setting the frame type flag bit; the decoding end receiving the bit stream from the encoding end; when a first frame immediately following a correctly received frame is lost, the decoding end judging a frame type of the first frame which is lost, a first lost frame for short hereinafter, according to frame type flag bits set by the encoding end and received by the decoding end prior to the first lost frame and when the first lost frame is a non-multi-harmonic frame, calculating Modified Discrete Cosine Transform, MDCT, coefficients of the first lost frame by using MDCT coefficients of one or more frames prior to the first lost frame; the decoding end obtaining an initially compensated signal of the first lost frame according to the MDCT coefficients of the first lost frame; and the decoding end performing a first class of waveform adjustment on the initially compensated signal of the first lost frame to obtain an adjusted time-domain signal of the first lost frame; wherein, judging a frame type of a first lost frame according to the frame type flag bits set by the encoding end and received by the decoding end prior to the first lost frame comprises: acquiring a frame type flag of each of n frames prior to the first lost frame, and if a number of multi-harmonic frames in the prior n frames is larger than a second threshold n 0, wherein n and n 0 are integers and 0≤ n 0 ≤ n, n ≥ 1, considering the first lost frame as a multi-harmonic frame and setting the frame type flag as a multi-harmonic type; and if the number is not larger than the second threshold, considering the first lost frame as a non-multi-harmonic frame and setting the frame type flag as a non-multi-harmonic type.