The invention provides a compact illuminator for a DPM (direct part marking) scanner, and the compact illuminator is used for executing the dual-field, multi-color, multidirectional and multi-distanceillumination functions. The illuminator can combine a direction for the short contact distance and long distance bar-code reading to selectively provide dark illumination and bright illumination through broadband spectrum white color or narrowband color. Specifically, the illuminator comprises a front edge illuminator with a customized LED optical device, a dome diffuser, an LED board assembly, and a reflection casing pipe which is arranged around the dome diffuser, The board assembly can further comprise an alternative on/off multi-point-source light field point illumination system. A methodfor scanning a DPM mark mainly comprises the steps: generating illuminating light through an illumination module; lighting the DPM mark; detecting the reflected and/or scattered light; capturing andcombining at least two continuous images with the DPM mark under different illumination conditions, and then processing and decoding the obtained images.