Value chain accounting is product of the combination of the value chain management theory, accounting theory and information technology and is the new area of the accounting to adapt to economic development. This paper discussed the functions and basic assumptions of value chain accounting. It puts forward the functions of value chain accounting which includes: real-time reflecting, real-time multidimensional controlling and predicting, decision-making and so on; the assumptions of value chain accounting includes: main body assumption of accounting, the elastic stage accounting assumption under the continuous operating, value measurement hypothesis and so on.