Halotherapy (HT), originated from Speleotherapy in salt mines, which is a therapeutic culture and is an alternative treatment method in western countries. In Thailand, HT in the simulated salt cave. This method helps to recover in many health issues, such as asthma, respiratory disease, certain skin diseases, and air allergies which are often found today. The problem is ordinary people are difficult to access this therapy owing to the rare service place and the price relatively high. These may be due to the high cost of the built salt cave and the equipment for generating salt mist in spa business. This research study aimed to design and develop a salt-mist generation control unit (SMGCU) or high-pressure salt spray for the HT in the spa business, covering high-performance salt sprayer and inexpensive when compared with the imported equipment. It also designed with a temperature and humidity controller (Temperature and Humidity Controller) that can detect temperature from (-20-80 ?C) and humidity range from 0-100% with displayed on Nextion and mobile phone with application installed. The device developed by using a 3 meters width, 4 meters long and 2.7 meters height spa room. Based on the performance test of the ultrasonic spray headed and SMGCU in terms of temperature and humidity, the results indicate that the SMGCU can measure temperature and humidity effectively. Additionally, when testing the overall performance of the SMGCU, it founded that it feasibly operated efficiently as the earlier given size and condition's room at the lower fixed cost as well.