The essence of the electricity market settlement is the distribution of the interests among market participants. Efficient and accurate settlement is the foundation of the steady and orderly development of the electricity market. Nowadays, China is pushing ahead comprehensive electricity market reform. As the pacesetter of the electricity market reform, Guangdong has faced many challenges in the mid-long term market settlement. Balanced budget is the main line of the Guangdong electricity market settlement mechanism design. The decoupling of the regulated market and the deregulated market settlement, two-level settlement of the immature regional market, deviation settlement in the generation side, flexible retail settlement, generation right settlement are adopted to achieve budget balance. The settlement mechanism of Guangdong electricity market is reviewed, the characteristics of deviation settlement mechanism design at home and abroad are compared and analyzed. Guangdong electricity trading system is introduced, and case studies are conducted on the settlement of Guangdong electricity market. Hope that this paper can provide beneficial references for the electricity market construction in China. This work is supported by Science and Technology Project of China Southern Power Grid Ltd. (No. GDKJXM20173113) and National Natural Science Foundation of China (No. 51537005).