Aim: The purpose of this study is to explore the use of holmium laser in gastroenterology: the effectiveness of EUS-guided holmium laser ablation to pancreatic primary implantation tumor in nude mouse, in order to provide the experiment evidences of clinical practice of holmium laser. Methods: Twenty 4-6-week male nude mice were chosen and the pancreatic cancer cell line SW1990 was vaccinated into the pancreas of nude mice. Then the vaccinated nude mice were evenly divided into two groups randomly: the treatment group and the control group. The treatment group mice were underwent the EUS-guided holmium laser ablation to the pancreatic tumor. And no preventions were given to the control group. The volume of the tumors of the two groups were measured under EUS at below time points: 7d, 14d and 28d after ablation. The activities, appetites and psychosis of all nude mice were evaluated in the meantime. At 28d after ablation, all the nude mice were dissected and the lesion of pancreas was complete sliced for H&E staining. Result: All the nude mice could tolerate the procedure. There were no complications in the treatment group mice. The figures of the control groups mice were extremely emaciate. There was obviously different in the changes of the tumor volume. HE staining showed the coagulation necrosis in the ablation area. Conclusion: EUS-guided holmium laser of the pancreatic primary implantation carcinoma in nude mice was effective. It mainly produced coagulative necrosis in the ablation area.