Abstract: In order to improve the monitoring accuracy of oil volume for arbitrary oil tank, the three-dimensional model of the target oil tank was established at first, using BIM technology in this paper, and then the model will be cut several times with different height that selected at random to simulate the changing process of oil level. After that, the total volume of the model and the residual volume of the model after cutting every time was calculated using BIM calculation function.Finally, under the application of least square fitting polynomial method, the oil consumption curve was obtained according to the data of cutting height percentage and volume percentage. Due to the better adaptability of BIM technology, the model of oil tank with any shape can be created and calculate its volume quickly. It is proved that the method with 96.39%accuracy is practicable by comparing the manual refueling volume with the system refueling volume within one month from four special-shaped oil tanks. Compared to other calculation techniques, this method is simple in operation, low cost and high accuracy, thus it has extremely wide application prospect in the field of oil volume monitoring on engineering machinery.