The embodiment of the invention discloses a transmission device, a transmission system and a transmission method for indoor multisensor data based on optical communication. The transmission device comprises an optical transmission module and an optical receiving module, wherein the optical transmitting module comprises a light emitting diode; the optical receiving module comprises a light sensor;the transmission device further comprises a processor, a memory, an internal control register and an external interface; the processor is electrically connected with the memory, the internal control register, the external interface, the optical transmission module and the optical receiving module; the external interface is used for connecting a plurality of corresponding sensors. According to theembodiment of the invention, optical communication is adopted to replace radio frequency communication and a serial port protocol is compatible with an optical communication protocol by protocol conversion; the transmission device is used as a node of a sensing network, so that interface compatibility of the sensing network node, node layout simplicity, communication reliability of the sensing network and the safety of a sensing network layout environment are improved, and electromagnetic pollution of sensing network layout is reduced.