EUS-guided pseudocyst drainage has been used world widely. Now, most endoscopists tend to place several stents to drain the content of cyst into GI tract. In the investigators experience, a modified naso-pancreatic tube drainage was more safer, easier and cheaper than placement of stents. Moreover, none of pseudocysts(total 19) drained by this modified naso-pancreatic tube drainage method were found recurrent with a follow up period from 3 months-34 months. So, the investigators designed this prospective random comparing study to confirm the result.

Inclusion Criteria:

1. Adults with ages from 18-80 years old.
2. The pseudocysts were formed more than 3 months.
3. The size of pseudocyst is more than 5 cm.
4. The patient has the symptoms related with the pseudocyst.
5. The distance between gastric and the wall of the pseudocyst is less than 1 cm from CT image.
6. The consent form has been signed.

Exclusion Criteria:

1. The patient can't accept the endoscopic procedure.
2. The patient has blood coagulation dysfunction.
3. The patient has mental disorders.
4. The patient has mild or severe cardiorespiratory insufficiency.
5. The patient has hypertension and can't be controlled to safe level.
6. Diabetics whose blood sugar level can't be controlled to safe level.
7. Patients with alcohol dependence
8. Pregnant and lactating women.
9. The patients the investigator don't think suitable for this study.