Ultrasonic humidifier in the recent years becomes more favorable technology on air conditioning system. High frequency surface vibration below water layer created by a piezoelectric transducer to make atomization of water on the surface of piezoelectric transducer. Application of the mist generated for air conditioning system need to investigated their relative humidity and dry temperature of the air that will be conditioned. Testing model and simulation of ultrasonic humidifier was developped to understand influence of mist generated on relative humidity and dry temperature of the air. The testing model have been investigated their inlet parameters (e.g., air temperature, air humidity, water temperature, and air velocity) it’s influenced on outlet parameters as regenerative performance of ultrasonic humidifier. Humidification process on ultrasonic humidifier have been investigated for effective humidification process that is 0.0186 kg/s air mass flow rate and water layer thickness about 3.5 – 4.5 cm. It can be provided for optimization design on application of ultrasonic humidifier.