For the past few years, Germanium-based semiconductor spintronics has attracted much interest due to its integration potential into mainstream semiconductor technology. The main challenges in developing modern semiconductor spintronics are the generation, detection, and manipulation of spin currents. Here, the transport characteristics of a spin current generated by spin pumping through a GeBi semiconductor barrier in Y3Fe5O12/GeBi/Pt heterostructures were investigated systematically. The effective spin mixing conductance and inverse spin Hall voltage to quantitatively describe the spin transport characteristics were extracted. The spin injection efficiency in the Y3Fe5O12/GeBi/Pt heterostructures is comparable to that of the Y3Fe5O12/Pt bilayer and the inverse spin Hall voltage exponential decays with the increase of the barrier thickness. Furthermore, the band gap of the GeBi layer was tuned by changing the Bi content. The spin injection efficiency at the YIG/semiconductor interface and the spin transportation within the semiconductor barrier were related to the band gap of the GeBi layer. Our results may be used as guidelines for the fabrication of the efficient spin transmission structures and lead to further studies on the impacts of the different kinds of the barrier materials.