The invention discloses a latent heat energy saving device of an outdoor machine of an air conditioning unit. The latent heat energy saving device of the outdoor machine of the air conditioning unit comprises a multi-hole hydrophilic material module, a water circulation system and a monitor, wherein the multi-hole hydrophilic material module comprises multi-hole hydrophilic materials, a water spraying disk, a water collecting disk, a water spray nozzle, a metal plate connection plate or a soft connection plate and a temperature-humidity sensor; the water circulation system comprises a water tank, a pump group, a spraying water supply pipe, a water supply pipe of the water tank, a return water pipe, a draining pipe, a magnetic valve of the spraying water supply pipe, a ball valve of the water supply pipe of the water tank, a magnetic valve of the draining pipe and a float switch; the water circulation system is used for providing circulation water source for the multi-hole hydrophilic material module; the multi-hole hydrophilic material module is used for providing water screens of a wind inlet side of the outdoor machine; and the temperature-humidity sensor, the magnetic valve of the spraying water supply pipe, the magnetic valve of the spraying water supply pipe, the magnetic valve of the draining pipe and the pump group are correspondingly connected with the monitor. The latent heat energy saving device is capable of effectively reducing the air inlet temperature of the outdoor machine of the air conditioning unit after being connected with the outdoor machine, accordingly the operation efficiency of an air conditioner is reduced, electric power is saved, and 18 to 36 % power is saved.