The invention discloses a broadband microscopic imaging spectrum system and a wavelength conversion rapid focusing control method thereof. The system comprises a microscope, a multiple optical paths switching device, an optical path controller, a light splitting unit, an Intensified Charge Coupled Device (ICCD), a light splitting unit controller, an image acquisition unit, a driving motor, an objective table, an objective table support, a position sensor, a light source and light splitting unit support, a focusing controller, a 2*1 optical path coupler, a reflection common light source, a reflection laser light source, a transmission common light source, a transmission laser light source, a light source controller, an image registering and controlling unit, a power supply module, and a computer. According to wavelength change, the system can automatically adjust a height of the objective table, rapid compensation of focal length change caused by the wavelength change is realized, and an acquired single wave band image can be subjected to pixel level registering. According to the invention, an imaging spectrum range is wide, ultraviolet, visible light and infrared light are covered, a microscopic image and spectrum information of a sample are obtained simultaneously, and the detection sample can be subjected to structural and functional identification and analysis.