The 20 morphological parameters of the sagittal otolith were applied to investigate the Trichiurus lepturus samples collected from June to August 2017 in the Gulf of Oman, Iran. The principal component analysis (PCA) of data set was carried out to evaluate the growth pattern of the sagittal otolith. The results show that the outline of the sagittal otolith is elongated spindle with a deep and prominent excisura major. Both rostrum and anti-rostrum are protruding, and the former extends forward and is longer than the latter in length. The principal component analysis revealed that the total statolith length (L₁), total statolith height (L₂), distance from the core to the rostrum (L₆), distance from the rostrum to the intersection (L₁₇), total rostrum length (L₁₉), and distance from the anti-rostrum to the intersection (L₂₀) were used as typical morphological characteristics of the T. lepturus otolith. All parts of the sagittal otolith are allometric growth during the whole life, such as the length and height of otolith, the rostrum and the anti-rostrum.The growth rate of the anti-rostrum is faster than the rostrum. The L₁ and L₂ of otolith have logarithmic correlation with anal length. A power function exists between the L₆ and anal length.The relationship between the L₂ and body mass is logarithmic. The L₁ and L₆ show a power function with body mass. The results of this study provide basic data for the population identification and age determination of T. lepturus.