The invention relates to a data sending method for reducing the multi-path delay interference, which comprises: based on the modulated data signal, using the emit impulse model relative to the frequency block used to transmit said data signal, to generate one signal at one mark period that not comprises circle prefix CP; via judging if the multi-path delay expansion is larger than the length of circle prefix CP, to judge if needs to increase the length of circle prefix CP; if needs, repeating transmitting the signal as the increased circle prefix information to be sent out with the circle prefix CP; the signal sending method comprises: sending said signal at the tail of present mark and before the tail circle prefix signal of next mark, or sending said signal at the back of circle prefix of present mark and the most front of next mark. The invention can increase the length of circle prefix to reduce the interference of multi-path delay, based on different fading conditions and different users.