The invention discloses a hydraulically-sprayed substrate for slope protection, which comprises Saccharum arundinaceum seeds, fibers, a water-retaining agent, a binder and a fertilizer according to aweight ratio of (8-12):200:5:1:50. According to the invention, the whole-plant Saccharum arundinaceum hydraulically-sprayed substrate for slope protection using the Saccharum arundinaceum seeds as a seed source and the Saccharum arundinaceum straws as a fiber source is developed, no additional fibers are added to the hydraulically-sprayed substrate, the slope protection level can be raised, and the lawn construction cost can be reduced; meanwhile, the problem of difficulty in harvesting and cleaning the Saccharum arundinaceum seeds is solved.