In the large-scale cross-regional power market, the transmission price of “one price for one line” is difficult to promote the optimization of resource allocation. Meanwhile, energy transmission and loss are closely related to energy sources and routes. This paper proposes a nodal price mechanism based on transmission fee apportionment and energy volume decomposition. Firstly, a transmission pricing method based on megawatt hour kilometer apportionment is proposed to make transmission pricing only related to distance and transmission volume, thus enhancing the fairness of transmission price for every participant. Secondly, a method of down-stream decomposition of energy quantity based on path tracing is proposed. By tracing the energy distribution results, the decomposition sequence and downstream decomposition are determined to clarify the source and path of energy quantity, so as to calculate the energy loss price and form the final node price. Finally, an example is given to verify the effectiveness of the proposed mechanism.