The precautions for pulmonary function tests for asthma include stopping asthma medications, keeping a quiet state, and eliminating contraindications. 1. Discontinue asthma medication: asthma patients must stop using asthma medication before the lung function test, the specific time of discontinuation should follow the doctor’s instructions. 2. Maintain a quiet state: before the examination, pay attention not to carry out strenuous exercise, keep a stable state of mind, adjust the breathing before the examination of lung function, and then do the examination after breathing steadily. 3. Exclude contraindications: if there is also blood pressure instability or heart attack patients, temporarily can not do pulmonary function test. If the patient has ventilation dysfunction, inform the doctor in advance. Asthma to do lung function test before, can not eat a lot of food can not be too hungry, the day of the test can not drink strong tea, cola and other stimulating drinks, so as not to affect the test results.