Abstract: To investigate the release pattern of top coal in combined mining, a mesh-free numerical calculation model based on the Smoothed Particle Hydrodynamics (SPH) method was proposed. The model employs the governing equations of continuum mechanics, combined with the constitutive relationship of elastoplastic soil and the Drucker-Prager yield criterion, to simulate the collapse, transportation, and release process of top coal particles. Considering the actual coal unloading and transportation process in the mining field, a scraper conveyor model was also constructed to simulate the horizontal release of top coal and bottom coal transportation along the working face, obtaining the variation laws of the coal-rock interface and coal flow velocity under different scraper speeds. The results show that: the non-cohesive soil constitutive model can effectively simulate the flow behavior of particles, and by setting material parameters such as the friction angle and modulus, it avoids the indefinite parameter problem of traditional DEM models; after the coal flow velocity stabilizes, the stress distribution near the unloading mouth presents a "double-peak" appearance; the scraper speed significantly affects the unloading time, but has a smaller impact on the final coal-rock interface and the shape of the released body; simultaneous unloading of multiple supports requires consideration of the scraper's transportation capacity, and interference between bottom coal from different supports may lead to blocking effects; the "stop unloading when seeing gangue" criterion leads to differences in unloading amounts from different unloading mouths, with a standard deviation of top coal unloading volume from 40 unloading mouths (7.52 m2) being higher than that of automatic unloading (1.93 m2).