Light-emitting diode (LEDs) have a promising prospect because of its outstanding advantages: 1) long lifetime, 2) environmentally friendly, 3) flexibility of color mixing, 4) high illumination efficiency, etc. Based on the electrical characteristics of LEDs, a constant current driver is needed to support the LED working performance. With the wide applications of LEDs, many new technologies are presented. In this paper, advantages and disadvantages of different LED drivers are discussed. A detailed technology review is presented which is good for researchers and engineers to make right choices in design and selection of LED drivers.