Abstract: 【Objective】 This study provided a detailed description of the morphological characteristics, damage symptoms, oviposition behavior of adults and oviposition preference of Auletomorphus montanus, aiming to provide a theoretical basis for the field identification of A. montanus, research on its adaptability to host plants, and the formulation of comprehensive control strategies. 【Method】 Methods such as field investigation, video recording and indoor microscopic observation were employed to record and analyze morphological characteristics of A. montanus, damage symptoms on young shoots of mango, and to study oviposition behavior of adults and oviposition preference on young shoots of mango trees. 【Result】 Adult A. montanus exhibited blue-green color, characterized by a slender and slightly curved beak. The antennae of male A. montanus were attached near the 1/4 position of the beak base, while the antennae of female A. montanus were attached near the 1/5 position. The oviposition behavior of female A. montanus comprised seven discrete categories of behavior: walking, boring cutting holes, boring oviposition holes, oviposition, boring again, hiding, and leaving.The average duration for each type of behavior was recorded as follows: boring cutting holes 33.24 s, boring oviposition holes 144.92 s, oviposition 25.25 s, boring again 80.30 s, and hiding 19.29 s. During oviposition, A. montanus first used its beak to consecutively bore cutting holes on young shoots of mango trees, forming several circles of closely spaced holes in a spiral shape. Subsequently, it bored consecutively oviposition holes above the cutting holes and created larger egg chambers at the bottom of the oviposition holes within reach of its beak. Finally, several oviposition holes were formed on young shoots in a nearly linear arrangement. During the process of boring oviposition holes, the insect randomly selected several oviposition holes to lay eggs, usually, one egg per oviposition hole, with 2 to 8 eggs laid per young shoot. When both top and lateral shoots of different thicknesses were present simultaneously, 93.33% of female A.montanus preferred to oviposit eggs on the thicker top shoots. 【Conclusion】 A. montanus displays complex oviposition behavior, including a unique cutting process before oviposition. Female A. montanus exhibits a pre-ference for ovipositing eggs on thicker young shoots. In the field, damage symptoms by A. montanus can be identified by nearly spiral and closely arranged cutting holes and nearly linear arrangement of oviposition holes.