Hand vein image has been widely used in biological recognition, auxiliary medical and other fields. People with age, height, weight, gender differences have distinction in fat thickness of the back of hand, so the contrast and sharpness of their hand vein images are different too, which may affect the results of applications. In this paper, a hand vein image acquisition system is given and the hand vein images of people from the age of 3 to 60 are obtained in various conditions. The effect on the images caused by ages, genders, BMI (body mass index) and FMI (fat mass index) are researched and the statistical characteristics of the images are analyzed. The types of applicable people are also proposed for applications.