Abstract: With the progress of low-power research on embedded real-time systems, software energy consumption has an efficient effect on the system and develops towards quantitative analysis. Aiming to the problem that the modeling and analysis of embedded real-time system is difficult to effectively take into account software energy consumption, this paper proposes a method for modeling and analyzing software energy consumption of embedded real-time system based on process algebra. Priced timed CSP is proposed by extending price information on timed CSP, and the power consumption of instructions in embedded real-time systems is mapped into the price of priced timed CSP. The energy consumption of embedded real-time software can be modeled and optimized by using priced timed CSP. The optimal path algorithms are proposed to check the power consumption satisfyability of single instruction and calculate the minimum energy consumption reachability path of embedded real-time systems. This formal method improves the accuracy and efficiency of energy calculation, and the calculation results can be used to quantitatively analyze and optimize the energy consumption of embedded real-time systems.