Abstract: To investigate the stress response characteristics and adaptation mechanisms of Stichopus chloronotus under mechanical stress, this study selected individuals with an average weight of 127.48±13.16 g and subjected them to physical vibration as a form of mechanical stress. Morphological changes were monitored during the two-hour stress period and post-stress recovery, while levels of catecholamine hormones and immune-related indicators in the coelomic fluid were measured. The results showed that during the initial phase of stress, the sea cucumbers exhibited an immediate stress response, characterized by a sharp significant increase in norepinephrine (NE) levels and a decrease in dopamine (DA) levels, aiding the organism in coping with external stimuli. During this stage, phenomena such as skin peeling and evisceration were prone to occur. As the stress continued, between 40–60 minutes, the activities of immune enzymes such as acid phosphatase (ACP) and superoxide dismutase (SOD) in the coelomic fluid, as well as the total density of coelomocytes and the density of amoebocyte, peaked. This phase was marked by a high incidence of individual stress responses, indicating a state of elevated physiological load. In the later stage of stress exposure, the sea cucumbers gradually became limp and exhibited reduced activity. The density of repair-related coelomocytes, such as spherulocyte and fusiform cells, increased, suggesting possible internal damage and the activation of repair mechanisms. In contrast, the density of immune cells such as phagocytes was significantly lower than initial levels, indicating that prolonged stress exerted an inhibitory effect on the immune system of the sea cucumbers. After the cessation of stress, the sea cucumbers remained limp and showed significantly reduced sensitivity to external stimuli. The findings demonstrate that continuous mechanical stress during transportation can lead to impaired immune function and diminished stress sensitivity in greenfish sea cucumbers, thereby increasing their susceptibility to diseases and mortality. Therefore, optimizing sea cucumber transportation practices through key measures such as reducing vibration intensity and limiting transport duration to within 60 minutes is of significant importance for reducing industrial losses and protecting tropical sea cucumber resources.