This study aims to develop a cold smoking equipment by improving the air circulation system in a fish smoking equipment with the position of the fish hanging vertically. The components used are DS18b20 sensor, MQ-2 sensor, arduino microcontroller, LCD, micro SD. Cold smoke testing is done by monitoring the temperature and concentration of smoke. The type of fish used in this study is the type of flying fish (Decapterus). The analysis used to determine the outcome of cold-smoked fish is water content. The results showed that the average temperature in the smoking room was (23.18-44.81)°C. While the smoke concentration obtained is (230-252) ppm Temperature and smoke concentration as desired and the results of the sensor data recording are stored in micro SD. The average value of the water content of smoked fish is (25.53%-32.45)%. The lowest water content of smoked flying fish is 25.53% at 6 hours fogging duration and the highest water content of floating fish is 32.45% at 3 hours fogging duration.