A method and an apparatus for transmitting a physical random access channel signal are disclosed by in the present invention. The method includes: when transmitting a physical random access channel (PRACH) signal, a terminal carries out pre-compensation for the frequency domain signal according to the estimated frequency spectrum gain of downlink channel, converting it into the time domain signal and transmits it to the base station. In the present invention, by way of measuring the spectral response of the downlink channel and carrying out pre-compensation for the frequency selective fading when transmitting the PRACH signal, using the symmetry of the uplink channel and downlink channel in the TD system, the adverse effect on the PRACH detection due to multipath channel could be effectively eliminated and the detection probability of the PRACH signal and measuring accuracy of transmission delay could be improved.