Objectives: To assess the efficacy of tadalafil de-escalation in the therapeutic effects of psychogenic erectile dysfunction (ED) during the 3 months extension phase. Methods: A total of 90 men with mild to severe psychogenic ED were randomly divided into 2 groups: tadalafil 5 mg group and tadalafil de-escalation group. Efficacy assessments included the 5-item version of International Index of Erectile Function (IIEF-5), the Sexual Encounter Profile (SEP) questionnaires, Psychological and Interpersonal Relationship Scales (PAIRS), Erection Hardness Score (EHS). Results: Compared with the baseline, tadalafil 5 mg and de-escalation groups enhanced all efficacy outcomes. Patients receiving tadalafil 5 mg and de-escalation experienced a significant mean improvement in the psychogenic erectile function domain of the IIEF-5 from the baseline (p < 0.01). The mean change from baseline was significantly higher for the tadalafil de-escalation group than for the tadalafil 5 mg group (p < 0.05). Response to SEP3, PAIRS and EHS was significantly higher in the tadalafil de-escalation group than in the tadalafil 5 mg group (p < 0.05). The severity of ED in the tadalafil de-escalation group had reduced after treatment. It was also significantly better than those in the tadalafil 5 mg group (p < 0.05). Conclusion: Tadalafil de-escalation significantly improved the erectile function among psychogenic ED patients. This implies that tadalafil de-escalation treatment for psychogenic ED is worthy of further clinical practice and research.