Inclusion Criteria:  Age: between 18- and 75-years old; Patients definitely diagnosed with chronic spontaneous urticaria according to 'Guideline for diagnosis and treatment of urticaria in China (2018) '; or chronic spontaneous urticaria has been diagnosed in the past. Patients taking antihistamines daily ( one kind or two to three kinds in combination, with a standard- or doubled-dose of each kind of antihistamines) for at least one week and remain symptomatic with a UAS7 score of not less than 16; Written informed consent was obtained, and the patient volunteers to participate in the project and complete the project as required.  Exclusion Criteria:  Patients with severe diseases of heart, brain, lungs, liver, kidney or blood system; patients experienced organ transplantation; Patients with any acute severe infection such as pyemia and cellulitis, active tuberculosis, or an infection history of human immunodeficiency virus (HIV); Patients have a clear history of allergy to rhIL-2; Patients receiving Interleukin-2 treatment in the last 3 months by subcutaneous or intramuscular injection； Patients with drug abuse, alcohol abuse, or mental disorders that are unable to cooperate or adhere to treatment; Pregnant women, lactating women or women who are willing to conceive within 3 months; Patients receiving glucocorticoid treatment in the last 4 weeks; Patients receiving cyclosporin treatment in the last 90 days；Patients receiving tripterygium wilfordii polyglycoside treatment in the last 6 months；Patients receiving Omalizumab treatment in the last 1 year；Other drugs used previously should be identified whether they are in the washout period one by one, and patients who have taken drugs that may have an impact on the study should be excluded during the washout period or screened again for enrollment after the washout period； Patients who have participated in other clinical trials within 3 months before the screening.