Abstract: The reasonable stemming of blasting holes is fundamental to achieving high-quality open-pit blasting. Key factors influencing the effectiveness of stemming include the height and material used for stemming. Through a series of laboratory tests, this paper has developed a testing device that simulates the open-pit blasting process, enabling accurate measurements of burst velocity, height, and explosion pressure within the blasting chamber. This research reveals that an optimal stemming height significantly enhances energy utilization efficiency while reducing both explosive consumption and the number of required blast holes. Experimental results demonstrate that increasing the length of stemming effectively mitigates bursting effects in blasting holes. Although granite exhibits superior performance as a stemming material, considering cost-effectiveness, rock powder may be a more economical alternative. This research not only provides empirical support for open-pit blasting but also serves as a reference for material selection in practical blasting engineering.