Abstract: In the measurement of coal-water mixture concentration during hydraulic punching permeability enhancement operations, traditional methods—such as the cofferdam method, sedimentation tank method, and weighing hopper method—suffer from low efficiency and accuracy. Tuning fork sensor technology also falls short in terms of precision and consistency, while single laser detection techniques have limited applicability. To address these issues, a laser-based transmission-reflection fusion device for coal-water mixture concentration measurement was proposed. A laser source and a reflected-light photodetector were installed on one side of the transport pipeline, and a transmitted-light photodetector was installed on the opposite side. The laser beam was directed into the coal-water mixture through a convex lens, and the transmitted-and reflected-light photodetectors converted the received optical energy into corresponding digital signals. The digital signals were superimposed and then processed for grayscale transformation and feature region selection, which helped reduce computational complexity and eliminate interference. The corresponding grayscale values were then calculated, and the relationship between grayscale values and coal-water mixture concentrations was established through polynomial regression, thereby enabling concentration measurement. The application results showed that, for coal-water mixture concentrations ranging from 2% to 20%, the minimum measurement error was 0.043%, the maximum error was 0.343%, the average error was 0.126%, and the standard deviation was 0.116%, meeting the accuracy requirements of hydraulic punching permeability enhancement operations.