Abstract: Biological parameters, including growth, reproduction, and natural mortality, are critical factors influencing the stock assessment of albacore tuna (Thunnus alalunga). However, these parameters are often derived from disparate data sources, lacking internal consistency and uniformity. Moreover, they fail to cover the full lifecycle of T. alalunga, leading to uncertainties in stock assessment results. To address this, we constructed a full lifecycle dynamic energy budget (DEB) model for T. alalunga based on the DEB theory and available growth and reproduction data. Model parameters were estimated accordingly. The results demonstrated the following: ① The DEB model accurately fitted the growth process of T. alalunga throughout its life history, estimated its potential annual fecundity, and integrated the processes of growth, maturity, spawning, and mortality. Notably, the model provided a growth equation for T. alalunga larvae without requiring age and length data, which the von Bertalanffy growth function (VBGF) cannot accurately provide. ② According to DEB theory, the growth of T. alalunga exhibitd two distinct stages before and after sexual maturity. Before maturity, energy allocated to maturation is dissipated and not used for body weight gain. In contrast, after maturity, energy was stored for reproduction and also contributed to weight gain. Consequently, the length-weight relationship was influenced by the proportion of mature and immature individuals in the sample. Our results indicated that using a single power function to fit the length-weight relationship for both stages is inappropriate. ③ The natural mortality coefficient was typically assumed to be constant (e.g., 0.3/a) in T. alalunga stock assessments. However, our findings revealed that aging mortality varies significantly with age or length. Given the substantial impact of this assumption on stock assessment and management, we suggested that the natural mortality coefficient for T. alalunga should account for age- or length- dependent variation. Although parameter estimation in the DEB model was subject to uncertainty due to limited observation data, the model effectively and accurately integrated the growth, reproduction, and aging mortality processes of T. alalunga. This highlighted the valuable application of DEB models in such studies. The findings of this study provided scientific support for the growth analysis and improved stock assessment of T. alalunga.