Nanoparticles (NPs) and plant growth-promoting rhizobacteria (PGPR) are two kinds of additives that have obvious promotion effect on plant growth and development, but the effectiveness and influencing factors of their cooperation remain incompletely understood. Here, we conducted a global meta-analysis of 68 published studies to explore the potential effects of simultaneous exposure to NPs and PGPR on plants and the factors influencing the benefits of their cooperation. The results indicated that either individual or combined applications of PGPR and NPs were effective at promoting plant growth and development, but the advantages of cooperation were more obvious, especially for plants under stress conditions. Our results also illustrated that PGPRs species affected the efficiency of cooperation with NPs, with the Bacillus spp. and Pseudomonas spp. having the most significant positive effects. Exposure to NPs of 7-15 d and foliar application had the most significant effects on plant biomass, photosynthetic capacity and nutrient accumulation. Effects on plant antioxidant systems were associated with NPs type, size, application dose and exposure way, but were not significantly related to exposure duration. Our results emphasize the effectiveness of cooperation between PGPR and NPs, which provides a theoretical basis for the development of nano-biofertilizers (NBFs), and also provides support for the application and promotion of NBFs in agricultural production.