A kind of space thermal-ion imaging detector was investigated, which can be used in detecting a variety oftargetsource such as thermion, ultraviolet, X-rays etc. The output of the detector is a grayscale image of the target source, the detail information including the gradation level and gradation distribution of the image are obtained based on the intensity and thermal-ion uniformity of the target source. This paper conducted experiments to test the detector with target source of ultraviolet light.Performance parameters as follows have been detected; the resolution is better than 120 μm; the input-output linearity error is <±4% and the output uniformity is better than 97%.