Abstract: In order to improve the quality of bio-organic fertilizer, exogenous amino acids hydrolyzed from animal carcasses were utilized as additives into matured composts to create novel bio-organic fertilizers (BIOs) containing plant growth-promoting rhizobacteria SQR9. The effects of adding amounts of exogenous amino acids, types of organic manures (e.g, chicken manure, cow manure and Chinese medicine residue) and fermentation time on the number of inoculants, strain SQR9, were investigated. The results showed that addition of 20% amino acids resulted in more effective solid-state fermentation efficiency than other treatments. Inoculating strain SQR9 after pre-composting for three days showed obviously higher amounts of the functional microbes, with the highest number of 4×10⁸ CFU/g fertilizer in dry weight than those treatments without pre-composting (adding amino acids and inoculating bacteria meanwhile) with the highest number of 1.2×10⁸ CFU/g fertilizer in dry weight. The optimal inoculation amounts of strain SQR9 in chicken manure, cow dung and Chinese medicine residue composts were 10.0%, 7.5% and 10.0%, respectively, with optimal water content maintaining at around 40%. Moreover, the addition of amino acids increased the total N amount in all treatments. In conclusion, the addition of amino acids hydrolyzed from animal carcasses could effectively promote the growth of functional bacterial strains during solid-state fermentation.