A new apparatus-scanning laser beam micrometer was introduced. It is very stable and accurate and is used for non-invasive measuring the variation of size. This apparatus is not in fluenced by mechanical or chemical reactions caused by external factors,and the accuracy is ±1μm at 23±0.05℃. The device is provided with a temperture console. It can be used for the investigation of the expansion and contraction effect of biomaterials under different tempera ture. It is widely applicated in the st...