This instrument is used for separating and determining the volume of water, oil, and solid phases in oil-based drilling fluid samples. The device employs external heating distillation, with an Omron temperature controller to regulate the temperature. It features large-capacity distillation, where a fixed amount of drilling fluid (50ml) is heated at high temperatures, and the oil and water are separated and condensed, then dripped into a graduated cylinder. The percentage of the mass or volume of oil, water, and solid phases is calculated. Due to the use of large-capacity external heating, the test accuracy is improved compared to the conventional (20ml) method. The temperature is controlled by a temperature controller, which avoids the dry-burning (over-temperature) that can occur with internal heating. This instrument is simple to operate and can be used in both laboratory and field settings. The distillation body contains steel wool, which is the basis for increasing the solid phase concentration and the viscosity and filtration control of water-based drilling fluids. Its features include a simple structure and convenient operation, making it ideal for laboratory and field use.