assess the efficacy and safety of Salmeterol Xinafoate and Fluticasone Propinate Powder for inhalation (50ug/250ug) in combination with seretide to patients with Asthma.

a randomized, double-blind, double-dummy, positive-controlled, parallel-group trail.

Inclusion Criteria:

• Patients with asthma diagnosed according to the Global INitiative for Asthma (GINA) criteria.

  • Inadequate asthma control on an inhaled corticosteroids alone at a dose of ≤ 800 μg/day of budesonide, ≤ 1000μg/day of Beclomethasone; ≤ 500 μg/day of fluticasone
  • Inadequate asthma control on bronchodilators
  • Inadequate asthma control on an ICS (medium and low dose)-LABA combination
  • primarily diagnosed with asthma

• Positive bronchodilation test [an increase in of FEV1﹥200 ml and the FEV1 change﹥12% from the baseline] or PEF variation﹥20%

• Age between 18-70 years

• Patients should participate in the study voluntarily and sign informed consent;

• Female patients can participate if they are surgically sterile or completed menopause or females capable of having children and agree not to attempt pregnancy while receiving study therapy; Male patients can participate if they are surgically sterile or males capable of having children and agree not to attempt pregnancy while receiving study therapy.

Exclusion Criteria:

• Allergic to salmeterol, fluticasone propionate or to ventolin.
• Have a current diagnosis of chronic obstructive pulmonary disease (COPD), pneumonia, pneumothorax, atelectasis, pulmonary fibrosis, bronchopulmonary dysplasia, chronic bronchitis or other respiratory tract disorders (not including asthma).
• Any respiratory tract infection, sinus infection or eardrum infection within 4 weeks prior to the screening .visit
• History or severe cardiovascular disease or hematopoietic system disease (congestive heart failure, clinically relevant coronary heart disease, apoplexy, clinically relevant cardiac arrhythmias, aortic aneurysm, and uncontrolled hypertension (systolic blood pressure above 160mmHg or diastolic blood pressure above 100 mmHg continuously measured more than twice.))
• Patients treated with leukotriene antagonist, such as zafirlukast, pranlukast, and montelukast.
• Expected medication to improve asthma other than ventolin
• Subjects who suffer from serious, uncontrolled diseases (including psychological disorders), in researcher's opinion, under great risks.
• Hepatic dysfunction: aspartate amino transferase (AST) and alanine amino transferase (ALT) levels of > 2.0 × ULN; renal dysfunction: serum creatinine level of > ULN )
• A history of both HBV infection and HCV infection.
• In Human Immunodeficiency Virus (HIV)-positive status
• Subjects with uncontrolled diabetics or fasting glucose > 10mmol/L
• Use of any β-blocking agent, including eye-drops
• In oral glucocorticoid medication or a history of systemic corticosteroid medication within 30 days of the screening visit
• Subjects who participated in other clinical studies within 2 months
• Subjects who have previously enrolled into this study
• Pregnancy, breast-feeding or planned pregnancy during the study
• Researchers think that do not fit into the group.

Double Blind