The history, present situation and developing trend of soil loss tolerance research are out lined. The main content in Tvalue research including soil formation rate, soil nutrient loss, off-site sediment damage, relationship between soil loss and soil productivity, and gully prevention is discussed in details. The mathematical expression of soil loss tolerance and Tvalue criteria in different countries are also introduced. The existing problems in Tvalue research and significance of making double Tvalue research are analyzed as well.