ACC017 is an integrase inhibitor that will be evaluated for the treatment of HIV infection. This phase Ib/IIa, randomized, double-blind, parallel, dose ranging, placebo-controlled 'proof of concept' study is designed to evaluate the safety, tolerability, pharmacokinetics and antiviral effect of ACC017 monotherapy and combined with FTC/TAF by sequency versus placebo in treatment-nave HIV-1 infected adults. This study includes two stages, stage one is a single dose escalation, and all subjects will be co-administrated with FTC/TAF at 200 mg/25 mg on stage two. The study consists of a screening visit, baseline period, monotherapy period, and combination therapy period. Total 36 subjects will be randomized in a 5:1 ratio to receive one of three doses of ACC017 or placebo lasting for 10 days for monotherapy followed by 18 days for combination therapy.