Silos are widely used facilities in coal preparation plants and other material handling units, but the complex spatial configuration at the bottom of silos presents challenges for accurate calculation of concrete infill volume. This paper thoroughly investigates two distinct calculation methods: Firstly, a parameterized Excel-based approach is introduced, combining space segmentation technology, where the complex area is divided into n manageable sectors of arc-shaped surfaces. The total infill volume is approximated by accumulating the volumes of these segmented regions, referred to as the segmentation method. Secondly, employing principles of calculus, an analytical computation method is developed to determine the exact volume of the three-dimensional geometric body between the silo’s inner wall and the square opening, thus generating a more precise mathematical model. Through comparative analysis of these two methods and validation against actual measurements, it is found that the segmentation method offers the advantage of intuitive comprehension and expedient estimation, with an error margin of -0.90%. Conversely, the calculus method delivers higher theoretical precision and is suitable for accurate calculations in complex geometries, achieving an error rate as low as 0.46%. The research aims to optimize the calculation method of concrete filling quantity quantity in the silo of coal preparation plant, improve the calculation accuracy, and provide accurate reference basis for the subsequent design and construction of similar projects. [1-9]