To investigate the potential effects of varying irradiance levels and spectral compositions on the behavior and physiology of Apostichopus japonicus, a comprehensive study was undertaken. Experimental groups were established, including a dark control group, a red light treatment group (with irradiance levels of 1.0 W/m², 2.5 W/m², and 4.0 W/m²), and a white light treatment group (also at 1.0 W/m², 2.5 W/m², and 4.0 W/m²). Utilizing a custom-designed apparatus, we assessed feeding behavior, turning ability, and locomotor activity. Additionally, melatonin and cortisol levels were measured in Apostichopus japonicus over a 37-day trial period. The results indicated that under red light conditions, Apostichopus japonicus demonstrated enhanced performance in terms of feeding success rate, feeding speed, and responsiveness to external stimuli when compared to both the white light and dark conditions. Notably, at an irradiance level of 2.5 W/m² in red light, Apostichopus japonicus exhibited optimal overall performance. The red light treatment group displayed significantly faster movement speeds and longer travel distances within equivalent time frames compared to the white light and dark groups. Furthermore, the cortisol levels in the red light group were elevated relative to those in the white light and dark groups, while no statistically significant difference (P > 0.05) was observed in melatonin content. Based on these findings, it is recommended to employ the red light spectrum during the juvenile cultivation phase of Apostichopus japonicus, with an optimal irradiance level of 2.5 W/m². Additionally, it is advisable to avoid excessively high irradiance levels within the farming environment. This study not only provides a scientific foundation for understanding the optimal light conditions required for the behavioral patterns and growth of Apostichopus japonicus but also offers valuable insights for the sustainable development of its aquaculture.