The invention belongs to the technical field of airborne broadband modulation and demodulation, and particularly relates to a COFDM (Coded Orthogonal Frequency Division Multiplexing) modulating and demodulating method used for an airplane. The COFDM modulating and demodulating method used for the airplane comprises the following steps of: obtaining a digital baseband signal; dividing the digital baseband signal into multiple paths of signals; performing scrambling treatment, RS encoding treatment, convolutional encoding and interlacing treatment on each path of the signals in sequence to obtain corresponding interlaced data; performing OFDM (Orthogonal Frequency Division Multiplexing) time-domain differential modulation on each path of interlaced data to obtain corresponding OFDM symbols; performing inverse Fourier transformation on each OFDM symbol to obtain corresponding time-domain OFDM symbol data; inserting a cyclic prefix and a leading training sequence to the front end of each time-domain OFDM symbol data to obtain sending data; obtaining a to-be-sent pulse waveform and storing the to-be-sent pulse waveform; after receiving a signal emission command from an MAC (Media Access Control) layer, performing modulated emission on carrier waves by utilizing the stored pulse waveform.