The current invention involves a desorption corona beam ionization source/device for analyzing samples under atmospheric pressure without sample pretreatment. It includes a gas source, a gas flow tube, a gas flow heater, a metal tube, a DC power supply and a sample support/holder for placing the samples. A visible corona beam is formed at a sharply pointed tip at the exit of the metal tube when a stream of inert gas flows through the metal tube that is applied with a high DC voltage. The gas is heated for desorbing the analyte from solid samples and the desorbed species are ionized by the energized particles embedded in the corona beam. The ions formed are then transferred through an adjacent inlet into a mass spectrometer or other devices capable of analyzing ions. Visibility of the corona beam in the current invention greatly facilitates pinpointing a sampling area on the analyte and also makes profiling of sample surfaces possible.