热挤压法成型的卤化银多晶光纤，经不同温度热处理后；光纤的显微结构发生了变化．扫描电镜形貌分析结果显示；热处理温度Ｔ≤１７０℃，显微结构未发生变化，晶粒尺寸１～２μｍ． Ｔ＝２００℃时，晶粒尺寸１０～２００μｍ； Ｔ＝２５０℃时，晶粒尺寸２０～３０μｍ ；Ｔ＝３００℃时，晶粒尺寸３０～４０μｍ．光纤显微硬度测量结果也显示，热处理温度＞１７０℃后，光纤的显微硬度随热处理温度的升高而降低，在２００℃附近硬度降至最低值． Hot extrusion method of forming silver halide polycrystalline fiber, after heat treatment at different temperatures; optical fiber microstructure has changed. The results of scanning electron microscopy showed that the microstructure did not change with the temperature of T≤170 ℃, and the grain size was 1 ~ 2μm. At T = 200 ℃, the grain size is 10 ~ 200μm; At T = 250 ℃, the grain size is 20 ~ 30μm; At T = 300 ℃, the grain size is 30 ~ 40μm. Optical fiber microhardness measurement results also show that the heat treatment temperature> 170 ℃, the optical fiber hardness decreases with the increase of heat treatment temperature, the hardness decreases to a minimum near 200 ℃.