This study evaluates the clinical efficacy of Shuanghe Decoction in the treatment of unstable angina. All of the patients will be divided into 2 arms randomly. One of the arms will be treated by conventional western medicine, and the other one will be treated by Shuanghe Decoction at the base of conventional western medicine.

Shuanghe Decoction has the function of supplementing Qi and activating blood circulation, which will be used to treat patients with Qi deficiency and blood stasis syndrome.

Inclusion Criteria:

• Participants diagnosed with coronary heart disease through coronary angiography or coronary CTA;

Patients have at least one of these symptoms:

1. The stability of the nature of angina pectoris changes, that is, frequent attacks of angina pectoris, serious degree and prolonged duration;
2. Angina pectoris during rest;
3. The recent occurrence of angina pectoris caused by mild physical activity in the last month.

Exclusion Criteria:

• Patients diagnosed with stable angina; Patients with acute myocardial infarction; Chest pain caused by congenital heart disease, valvular heart disease, severe neurosis or arrhythmia; The heart function grade is III or IV; Patients with acute cerebral infarction; Patients complicated with other serious primary diseases; Patients with acute infection in recent 2 weeks; Uncontrolled hypertension (the resting blood pressure >160/95mmHg within one week); Diabetics emerged with serious diabetic complications; Patients can't finish the questionnaire due to abnormal mental and nervous or mental disorders; Pregnant or lactating women.