The invention relates to a preparation method of a scrap rubber powder-hard rubber composite reinforced by waste fibers from rubber reclaiming. In the preparation method, the high-performance scrap rubber powder-hard rubber composite reinforced by waste fibers is formed under the modifying action of sulfur and by mixing waste rubber powder subjected to surface activation and preprocessed waste fibers. The sulfur further modifies an existing rubber cross-linked network and rubber molecular chains to form gradient distribution of sulfur on a rubber powder-rubber powder interface. Meanwhile, waste fibers play a role in reinforcing a hard rubber material. The invention has the advantages that: the preparation method is simple and easy to implement; the raw materials are widely available and cheap; and the prepared material can be recycled and creates significant social, economic and environmental benefits.