As the resistant rate of the Helicobacter pylori to some common antibiotics was rising，the eradication rate of the Helicobacter pylori with the standard triple therapy failed to exceed 70% in China，and had to drop out of the first-line treatment recommendations. However, with the increase of treatment time, patients burden, adverse reactions of antibiotics or proton pump inhibitor (PPI) will also increase. Resistance to clarithromycin is the major cause of the failure to eradicate Helicobacter pylori. But, in terms of population, there are still more than 70% of the patients with clarithromycin sensitive. Under the guidance with susceptibility test，7-day standard triple therapy could be used. In this study, investigators will select the patients with infection of H. pylori and with clarithromycin sensitive. Eradication of Helicobacter pylori with triple therapy based on accurate susceptibility testing of clarithromycin will be studied. The treatment time will be assigned into 7 days,10 days and 14 days groups. Then, investigators will perform a sequencing for failed treatment patients in groups, such as drug resistance gene mutation, phenotype and genotype. Finally, investigators will compare the differences between the patients with triple therapy and traditional quadruple therapy.The incidence of adverse effects in the eradicate treatment will reduce at least 10% and avoid patients' unnecessary economic losses at least 400RMB per person.

Inclusion Criteria:

1. Age 18~70 years old, male or female, the first eradication therapy of H. pylori infection patients.
2. Symptoms of abdominal pain, bloating, acid efflux, belching, nausea, vomiting, heartburn, chest pain, vomiting, melena, etc.
3. Unused antibiotics, bismuth, H2 receptor antagonists or PPI by nearly 4 weeks
4. 13C-labelled urea breath test positive.
5. Agreed to Helicobacter pylori culture and sensitivity testing taken by endoscopy gastric biopsy specimens,and the result of culture was positive.
6. Agreed to Helicobacter pylori eradication therapy and cooperate with the eradication efficacy follow-up survey.

Exclusion Criteria:

1. Severe heart, liver, kidney dysfunction.
2. Pregnant or lactating women.
3. Complications of bleeding, perforation, pyloric obstruction, cancer.
4. Within 3 months before with the drugs involved in other drugs research.
5. Esophageal,gastrointestinal surgery history.
6. Patients can not properly express their complaints,such as psychosis, severe neurosis.
7. Taking NSIAD or alcohol abusers.
8. Allergic to amoxicillin or clarithromycin tested by susceptibility testing.