To improve the quality of palm kernel meal (PKM), the effect of solid-state fermentation (SSF) with Bacillus velezensis, Saccharomyces cerevisiae and Lactobacillus paracasei on nutritional components, anti-nutritional factor and antioxidant activity were investigated. The results show that inoculation ratio of three strains 4:2:1, inoculation amount 21%, moisture content 52%, fermentation temperature 34 °C and fermentation time 60 h were the optimal SSF conditions. After 60 h of fermentation, the content of neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), cellulose and hemicellulose in PKM were significantly decreased by 22.5%, 18.2%, 20.2%, 17.6% and 32.4%, respectively. Meanwhile, the content of crude protein, soluble protein, peptides, amino acids and reducing sugar were increased significantly by 27.3%, 193%, 134%, 16.3% and 228%, respectively. SSF significantly improved the total phenolic content, DPPH radical scavenging activity, hydroxyl radical scavenging activity and reducing power. In addition, in vitro dry matter digestibility (IVDMD) and in vitro crude protein digestibility (IVCPD) were increased. Scanning electron microscopy (SEM) analysis revealed microstructural alterations in PKM. The results indicate that SSF with B. velezensis, S. cerevisiae and L. paracasei is an effective and promising method to enhance the nutritional value and antioxidant activity of PKM, providing a feasible solution for increasing the utilization of PKM in animal feed.