The invention discloses a hardware TCP / IP protocol stack possessing active and passive transmission modes. The protocol stack comprises a data interface module, a TCP / IP protocol stack core module, a MAC module and a PHY chip. The TCP / IP protocol stack core module comprises a frame analysis unit, a network management unit, a frame packaging unit, a high speed hardware sending channel and a software sending channel. In the invention, two kinds of interfaces of a hardware transmission channel and a software transmission channel are simultaneously possessed, which provides great convenience for application layer function realization. The design possesses high flexibility and the structure is clear so that the protocol stack can be widely used for embedded sensing equipment. In the invention, priorities of responses of ARP, ICMP, TCP response and transmit and receive and the like are provided; and in a subsequent design, if a UDP protocol needs to be used or other protocols are added, a packaging and analysis module of a corresponding protocol only needs to be increased and the protocol can be realized.