Objective To systematically evaluate the multi-generational reproductive and developmental safety of long-term consumption of genetically modified maize expressing cry1Ab/cry2Aj and G10evo-EPSPS protein (double-resistant 12-5) in cynomolgus monkeys. Methods Thirty-six sexually mature cynomolgus monkeys (F0 generation, 6 males, 30 females) were randomly divided into a conventional diet group (CK), a genetically modified maize group (GM, 70% incorporation), and a non-genetically modified parental maize group (Non-GM). Animals were bred in a harem system at a 1:5 male-to-female ratio. Reproductive performance of the F0 and F1 generations was recorded, and F1/F2 offspring were systematically assessed for fetal appearance, neurobehavioral development, physical growth, and hematological/serum biochemical parameters. Results No significant differences were observed in F0 pregnancy rates (GM: 33, CK: 26, Non-GM: 29; P > 0.05) or overall F1 offspring survival (GM: 19, CK: 20, Non-GM: 14; χ2 = 3.141, P = 0.237). Reproductive performance of the F1 generation and survival of the F2 generation also showed no significant intergroup differences (P = 1.000). No fetal malformations were detected in any offspring. Behavioral neurodevelopmental scores, physical growth trends, and baseline physiological parameters (including 24 hematological and 19 serum biochemical indices) were consistent across all three groups. Conclusion Long-term consumption of cry1Ab/cry2Aj and G10evo-EPSPS transgenic maize has no adverse effects on parental fertility or early offspring development in cynomolgus monkeys, providing important non-human primate evidence for the food safety of this genetically modified crop.