Abstract
Measurement uncertainty is an important part of modern error theory; it is also an essential indicator to describe measurement quantitative result. Recently, GUM (Guide to the expression of Uncertainty in Measurement) which rose by seven international organizations such as ISO had been accepted extensively by most counties all over the world. Although our country do not agree with GUM, we stay the same with others counties in carry out GUM. This article introduces the development of the measurement uncertainty, the measurement uncertainty source, the conception of measurement uncertainty and how to calculate measurement uncertainty, at last two physics experiments were given to show how to calculate measurement uncertainty.
