Background This phase 3 trial is the first to evaluate the efficacy and safety of treatment with the systemic TNF‐α inhibitor, adalimumab, for Chinese patients with moderate‐to‐severe plaque psoriasis. Methods In the 12‐week, double‐blind, placebo‐controlled Period A, patients were randomized 4 : 1 to receive adalimumab 40 mg every‐other‐week (following a single 80 mg dose), or placebo every‐other‐week. In the subsequent 12‐week, open‐label, Period B, all patients received adalimumab 40 mg every‐other‐week starting at week 13, following a single, blinded dose at week 12 of adalimumab 80 mg or matching placebo (for patients receiving placebo or adalimumab in Period A respectively). In Period A, efficacy was analysed for all randomized patients and safety for all patients receiving ≥1 dose of the study drug. Results For the 425 patients in this study (87 placebo; 338 adalimumab), a higher percentage randomized to adalimumab achieved the primary endpoint of ≥75% improvement from baseline in PASI score (PASI 75) at week 12: placebo 11.5% (10/87); adalimumab 77.8% (263/338; P < 0.001). Physician's Global Assessment of clear to minimal was achieved at week 12 by 14.9% placebo (13/87) and 80.5% adalimumab (272/338; P < 0.001). For patients who received adalimumab at any time during the study (All‐adalimumab Population), treatment‐emergent adverse events (AEs) were reported by 63.4%; the most common was upper respiratory infection (16.1%). Serious AEs were reported by 3.5% of the All‐adalimumab Population, and serious infectious AEs by 1.2%, which include lung infection, pneumonia and tuberculosis 2 (0.5%) patients each. There was one death (chronic heart failure). Conclusion In these Chinese patients with moderate‐to‐severe psoriasis, a significantly greater percentage treated with adalimumab compared with placebo achieved efficacy endpoints at week 12 and efficacy was sustained to week 24. Safety results were consistent with the known adalimumab safety profile; no new safety signals were identified in the 24 weeks of treatment.