(a) Background: Omalizumab is an anti-IgE humanized monoclonal antibody marketed in China for the conventional treatment of poorly controlled moderate-to-severe allergic asthma. Numerous clinical trials have demonstrated the effectiveness of omalizumab, but the data from studies in actual clinical treatment are still relatively limited. (b) Methods: Thirty-two patients with moderate-to-severe allergic asthma treated with omalizumab on the basis of ICS-LABA (inhaled corticosteroids/long-acting beta2-agonist) were selected. Clinical characteristics before and after treatment were collected to analyze the relationship between changes in serum total IgE levels and peripheral blood EOS (eosinophil) levels, FEV1 (forced expiratory volume in 1 second), PEF (peak expiratory flow), OCS (oral glucocorticoid) dosage, ATC (asthma control test) score, and the number of acute exacerbations and the treatment response, in order to observe the efficacy of omalizumab in addition to primary therapy, and to investigate whether baseline clinical characteristics such as serum total IgE and EOS levels could predict a treatment response. (c) Results: Using the ACT score as an evaluation, 68.75% of patients benefited from omalizumab treatment at the end of 16 weeks. The response group has a reduction in OCS dosage (p-values of 0.026 and 0.039), a significant reduction in ACT scores (both p < 0.001), and a reduction in the number of acute exacerbations (p = 0.034 and 0.025, respectively) after omalizumab treatment. The binary logistics analysis of factors affecting the effectiveness of omalizumab in the treatment of allergic asthma were total serum IgE and the presence of comorbidities (p-values of 0.039 and 0.046, respectively). (d) Conclusions: Combining omalizumab with ICS-LABA for 16 weeks significantly improves asthma symptoms in Chinese adults and can be used as an add-on treatment. In addition, high serum IgE levels and the presence of comorbidities were predictors of its therapeutic efficacy.