The utility model discloses a temperature and humidity display device of a central air conditioning unit. The temperature and humidity display device comprises a programmable logic controller (PLC) module, a light-emitting diode (LED) display screen and an intelligent communication module, wherein the intelligent communication module is connected with the PLC module and converts analog quantity transmission to digital communication and transmits digital signals to the LED display screen. According to the temperature and humidity display device, data of an on-site temperature and humidity display screen are more precise, and zero error is achieved.