Embodiments of the present disclosure disclose a signal transmission apparatus and method, and a wireless access node, and relate to the field of communications technologies, so as to resolve a problem that a spectrum cannot be fully used. The method of the present disclosure includes: obtaining, by a wireless access node, configuration information for use to transmit a signal of a second carrier in coverage space of a first carrier, a spectrum occupied by the first carrier and a spectrum occupied by the second carrier overlap, and a subcarrier of the first carrier and a subcarrier of the second carrier are orthogonal; and transmitting, by the wireless access node, the signal of the second carrier according to the configuration information. The present disclosure is applicable to a scenario in which a signal of a carrier is transmitted in coverage space of another carrier.