For each patient, detection of HIV viral load and CD4+ T lymphocyte count is done at screening, and at weeks 4, 12, 24 and 48. The safety profile of RAL is monitored according to patients' complaints and the results of physical and laboratory examinations. Plasma HIV RNA viral loads are determined by HIV-1 Quantiplex(bDNA) assay approved by FDA. CD4+ T lymphocytes are counted with flow cytometry. Any drug-related adverse events that patients experience during treatment will be recorded, such as nausea, vomiting, abdominal pain, abodominal distension, diarrhea, fever, headache, dizzy, fatigue etc. Laboratory examinations cover blood, urine and stool routine, liver and renal function, electrolytes, blood glucose, blood lipid, electrocardiogram etc.