The invention relates to deep sea temperature measuring equipment based on optical communication, and belongs to the technical field of deep sea detection. The deep sea temperature measuring equipmentcomprises a mechanical arm, a temperature measuring device and a watertight cable. The mechanical arm comprises a driving arm and a clamping jaw installed at the moving end of the driving arm. The temperature measuring device comprises a temperature measuring unit and a communication transmission unit which are spaced to form a separation structure; the communication transmission unit is fixed onthe moving end, and the temperature measuring unit is clamped on the clamping jaw in a releasable manner; the temperature measuring unit and the communication transmission unit are in communication connection based on a bidirectional optical communication module group so as to output a temperature detection signal, to send the temperature detection signal back to a submersible vehicle through thewatertight cable, and to transmit a control signal sent by the submersible vehicle through the watertight cable to the temperature measuring unit. Based on the structural arrangement, control over deep sea detection is facilitated; the temperature measuring unit can be released when a detection front end is clamped so that most equipment can be recycled, the watertight cable can be prevented frombeing broken, and the equipment can be widely applied to the technical field of deep sea detection.