Disclosed are a three-dimensional vein identification device and method, a switch, and a mobile terminal. The device comprises: a light source, a microlens array, an image sensor, a three-dimensional vein image processor, and a three-dimensional vein identifier. The microlens array comprises an outer surface, an inner surface, and an edge part. The light source is provided at a side of the edge part. The image sensor is provided at a side of the inner surface. The image sensor is connected to the three-dimensional vein image processor. The three-dimensional vein image processor is connected to the three-dimensional vein identifier. Embodiments allow a reflected light shone on a finger of a user by the light source to be shone on the microlens array to produce two or three or more two-dimensional vein images, angular and depth transformation processing is performed with respect to the two-dimensional vein images by the three-dimensional vein image processor to acquire vein depths, and the two or three or more two-dimensional vein images are converted into one three-dimensional vein image on the basis of two or three or more vein depths, thus implementing three-dimensional vein identification of an increased degree of precision.