A method and system for single-PDP dual-stack serial dialing is provided. A mobile terminal sets a single-PDP dual-stack serial dialing parameter according to a parameter setting command transmitted by a host; then the mobile terminal initiates a PDP activation request to a mobile communication network according to a first dialing instruction transmitted by the host and the configured single-PDP dual-stack serial dialing parameter, acquires activation response information fed back by the mobile communication network, generates dialing response information according to the activation response information, and feeds back the dialing response information to the host, wherein the dialing response information includes cause reference information. And after receiving the dialing response information, the host can acquire a specific condition of the current mobile network according to the cause reference information included in the dialing response information to determine a dialing mode.