Objective: Based on statistical parametric mapping (SPM), this study analyzes the variability characteristics of lower limb drop jump movements in females with generalized joint hypermobility (GJH).Methods: Fifteen females with GJH (GJH group) were recruited based on the Beighton score and matched with 15 healthy females (control group). Kinematic and kinetic data were synchronously collected using the Qualisys infrared motion capture system and Kistler 3D force platform. Joint angles and torques were computed using OpenSim. Custom Matlab scripts were used to calculate the standard deviation curves of joint angles, and SPM was applied to analyze differences in movement variability between the groups during the eccentric, coupling, and concentric phases of drop jumps. Additionally, the maximum joint flexion angles and torques (mean and standard deviation) were computed to support the findings, and effect sizes were evaluated using Cohen's d.Results: Significant differences were observed between the two groups during various phases of the drop jump. In all statistically significant periods, the GJH group exhibited higher joint angle standard deviations compared to the control group (P < 0.05). Differences were primarily concentrated in joint flexion movements. During the coupling phase at different heights, the standard deviation of knee joint flexion angles in the GJH group consistently exceeded that of the control group (P < 0.001). Discrete variables showed significant differences in the standard deviation of maximum knee flexion angles at different heights: at 30 cm, P = 0.001, Cohen's d = 2.520; at 40 cm, P = 0.014, Cohen's d = 1.739; and at 50 cm, P = 0.005, Cohen's d = 1.768. No significant group differences were found in the mean values or standard deviations of maximum joint flexion angles and torques.Conclusion: Females with GJH exhibit higher movement variability during drop jumps compared to healthy females, particularly in knee flexion movements during the coupling phase. Excessive variability reflects insufficient motor control, reducing their ability to resist external disturbances and leading to high-risk movement patterns (e.g., excessive flexion or knee valgus).