The present invention relates to an optical analyzer for rapidly detecting reagent, which is to go with a carrier for carrying a color-rendering chip, including: a main body; an imaging unit set up in the main body; an optical reflection unit installed in the main body at an angle capable of reflecting the color-rendering chip image to the imaging unit, and is adjacent to the imaging unit at a distance conforming to the imaging focal length; a mobile module set in the main body for moving back and forth and located below the optical reflection unit, which has a carrier seat for placing the carrier. With the aforementioned structure, the present invention utilizes the optical reflection unit to reflect the image of the color-rendering chip to the imaging unit for extraction, namely using indirect way of extracting image to replace conventional direct way of extracting image to further reducing overall device size effectively and enhancing efficiency of space utilization.