Secondary succession is an crucial way of vegetation restoration in grasslands, but it requires a slow process. Accelerating the process is receiving increased research attention. The rhizosphere soil addition (RSA) of plants growing in the late secondary succession may become an crucial tool for the ecological restoration of grassland. However, the response of plant-soil-microbe characteristics in degraded grasslands to RSA requires further investigation. Herein, the herb Bothriochloa ischaemum typical of the late secondary succession in the loess area and the soil to be reclaimed in the mining area were used to test the effects of adding low (RSA1), medium (RSA2), high (RSA3) concentrations of rhizosphere soil on plant-soil-microbial properties through potting experiments. Results showed that RSA1, RSA2, and RSA3 significantly increased the biomass of Bothriochloa ischaemum leaves (74%, 117%, and 245%), stems (99%, 108%, and 394%), roots (58%, 133%, and 223%), and total biomass (77%, 119%, and 293%). However, it had no effect on plant or soil carbon content. RSA significantly increased only soil total phosphorus, soil available nitrogen, and water-soluble phosphorus. RSA3 significantly increased plant carbon content, whereas RSA1 and RSA2 decreased plant carbon content. RSA reduced the intensity of plant nitrogen limitation and increased the intensity of phosphorus limitation. RSA1 and RSA2 can also significantly increase the microbial nitrogen-phosphorus ratio; different intensities of RSA cannot significantly affect the microbial carbon-phosphorus ratio but can reduce the soil enzyme stoichiometry. RSA can mediate plant-soil-microbial nutrients, thereby promoting the recovery of grassland ecosystems.