Understanding the distribution characteristics of X.gladius can provide scientific basis for studying the habitat ecology of X.gladius,resource conservation and improving longline fishing gear.This paper highlights the results of domestic and international research on factors influencing the distribution and longline catch per unit effort (CPUE) of X.gladius,as well as the problems and proposes countermeasures to be taken for further research in the future.The results show that:1) X.gladius perform diurnal vertical movements,with a U-shaped movement pattern according to the changes of dissolved oxygen content in water layer,and generally distribute in the corresponding depth of 8.5-13.3 °C during the day and 23.6-26.2 °C during the night;2) X.gladius migrate to tropical waters for spawning and overwintering,and migrate to temperate waters for feeding; 3) X.gladius congregate in frontal areas and eddy fields;4) moonlight illumination affects the vertical movements of X.gladius,and moon phase may also be related to X.gladius spawning behavior;5) the catch rate of X.gladius in monofilament longline fishing is higher than that in polyfilament longline fishing,and the soaking time is positively correlated with the CPUE of X.gladius; 6) fluorescent rods in fishing gear can improve X.gladius CPUE,and the soaking time of fluorescent rods is positively correlated with X.gladius CPUE.The main shortcomings of the previous studies include:1) insufficient research on the relationship between climatic changes and the habitat change of X.gladius;2) less quantitative research on the effect of lunar illumination on X.gladius activity and the results are not robust;3) insufficient research on the effects of different hook types,hook offset and baits on X.gladius CPUE.The following issues are suggested for future research:1) increasing the testing experiments of TDR and CTD to study the effects of temperature,salinity,chlorophyll a and dissolved oxygen concentrations in different water layers on X.gladius distribution;2) using historical catch statistics and satellite remote sensing data to study the relationship between X.gladius distribution and marine environment in combination with changes in ocean monsoon and trade winds to find out the specific effects of climate change on X.gladius distribution;3) using illuminance meters to measure the illuminance of moonlight and quantitatively study the effects of monthly illuminance of moonlight on the vertical movements of X.gladius and their bait organisms and the spawning behavior of X.gladius; 4) further studying the effects of different hook types,hook offset and different baits on X.gladius CPUE.