Method disclosed is applied to an OFDM wireless transmission system which includes at least two OFDM symbols, and includes: adding a zero power padding ZP to a tail end of each of the at least two OFDM symbols; adding data of Nw consecutive points at one end of a first OFDM symbol of the at least two OFDM symbols to the ZP at the other end of the first OFDM symbol, so that the data of the Nw points is a prefix and/or a suffix of the first OFDM symbol, where the first OFDM symbol includes data of N points, N>Nw; and performing point multiplication processing with symmetric time domain window function on the data of the Nw points at the two ends of the first OFDM symbol to which the prefix and/or the suffix is added, so that a sum of point coefficients corresponding to the symmetric time domain window function is 1.