Objective: To study the role of potassium channel activator in treatment of asthma. Methods: Airway insufflation pressure measurement(AIP), bronchial alveolar lavage fluid(BALF) cells count and pathological analysis were employed to detect airway resistance variation and airway inflammatory cells infiltration following inhalation of ovalbumin. Results: BRL 55834(8 μg/kg) inhibited not only ovalbumin induced AIP increase but also inflammatory cells infiltration in sensitized guinea-pigs, it did not lower blood pressure. By contrast to BRL 55834, BRL 38227 (200 μg/kg) and aminophylline(25 mg/kg) inhibited ovalbumin induced inflammatory cells infiltration, but BRL 38227 lowered blood pressure markedly. Verapamil (0.5 mg/kg) had no effects on AIP increasing and inflammatory cells infiltration. Conclusions: BRL 55834, a selective potassium channel activator, not only decreases airway resistance, but also inhibits inflammatory cells infiltration, and this is beneficial for treatment of asthma.