Fiber-optic thermal radiation thermometry was studied using Er end doped silica fiber sensor. Visible light radiation peaks were clearly observed at k= 522nm and, 655nm, 800nm and 984nm from Er end doped silica fibers sensor. Theses peaks increase greatly with temperature of the sensor. Intensity ratio of thermally excited luminescence peaks at k= 522nm and 984nm, 1522/984, is suitable for the high temperature measurement. Two dimensional (2-D) temperature distributions in a flame are successfully visualized by X-Y scanning technique using Er end doped silica fiber sensor.