The article, after making an analysis of the concept of tourism in narrow sense, and tourism in broad sense, the consuming function of tourist service products as well as its invisible features, holds that it is necessary to define and calculate tourist adding value, using the proportion of tourist adding value in GDP to weigh up the position of tourism industry in the national economy, The unscientific formulation that "how many percentage the total income from tourism accounts for in GDP" which is prevalent in the tourist circle should not be used any more. The article, taking the data from Guangdong Province as a sample, raises the method of using tourist consuming minus coefficient to calculate tourist service adding value. The article, for the first time, makes a calculation of tourist adding value for nineteen provinces and municipalities.