Percutaneous ethanol injection (PEI) can dehydrate tumor cells and nearby vascular endothelial cells, coagulate and denature proteins, and eventually cause necrosis and fibrosis formation in tumor tissues. In 1983, Sugiura reported the treatment of liver cancer by percutaneous hepatic puncture and intratumoral injection of absolute ethanol under ultrasound guidance, which gained wide attention and application because of its ideal route of drug delivery, simple and safe operation, and minimally invasive characteristics. Many scholars also carried out extensive research related to ethanol injection for liver cancer in the 1980s. Xiaoguang ZHANG, Lanxi GENG et al. investigated the role of direct ethanol injection ex vivo and in patients with intermediate to advanced liver cancer. In 1990, Chung et al. reported the results of ethanol injection in controlling tumor rupture bleeding. For tumors <3 cm in diameter, direct percutaneous injection into the tumor is quite effective. With the continuous development of other treatment options, multi-point coverage or combination with TACE is now being adopted to improve treatment effects for single or multiple tumor(s) 3–5 cm in diameter.