Objective To evaluate the therapy efficacy of iloprost combined with low dose tadalafil in adult congenital heart disease(CHD)patients with severe pulmonary arterial hypertension(PAH).Methods Adult CHD patients with severe PAH were included and divided into the sequential combination therapy group[iloprost:10μg/inhalation,6 times per day for 6 months,and then add oral tadalafil(5 mg/d)till 12 months,n=32]and upfront combination therapy group[iloprost:10μg/inhalation,6 times per day combined with oral tadalafil(5 mg) Objective To evaluate the therapy efficacy of iloprost combined with low dose tadalafil in adult congenital heart disease (CHD) patients with severe pulmonary arterial hypertension (PAH). Methods Adult CHD patients with severe PAH were included and divided into the sequential combination therapy group [iloprost : 10 μg / inhalation, 6 times per day for 6 months, and then add oral tadalafil (5 mg / d) till 12 months, n = 32] and upfront combination therapy group [iloprost: 10 μg / inhalation, 6 times per day combined with oral tadalafil (5 mg)