The electrical properties of heterojunctions composed of polycrystalline films of beta-irondisilicide and n-type germanium substrate are investigated. The heterojunctions have been prepared by co-sputtering of iron and silicon on germanium substrate followed by thermal annealing. The samples were prepared over various annealing temperature and chemical compositions. Most of the samples showed rectifying characteristics in current-voltage characteristics measurement. However, large backward leakage current was observed. The result is consistent with that in the case of beta-irondisilicide/silicon heterojunctions. In addition, the leak current showed significant dependence on annealing condition and chemical composition. It was suggested that the high density of trap levels existing at the interface caused by diffusion of Fe into substrate induce the inadequate electrical properties of the samples.