The invention belongs to the technical field of medicines, and particularly relates to new application of guanosine, in particular to new application of guanosine in preparation of medicines for treating asthma or inhibitors of MAPK, NF-kappa B and STAT3. The invention aims to solve the problem that safer and more effective asthma treatment medicines need to be developed urgently in the prior art.It is found that in an in-vitro THP-1-derived macrophage inflammation model, guanosine inhibits generation of a proinflammatory factor IL-6 by inhibiting activation of MAPK and NF-kappa B; in an asthma mouse model, guanosine reduces OVA-IgE of mouse plasma, reduces generation of IL-4, IL-6 and IL-13, relieves airway high reactivity, and relieves lung tissue cell infiltration, airway inflammationand collagen deposition. In addition, the expression levels of p-p38 MAPK, p-p65 NF-kappa B, p-I kappa B alpha and p-STAT3 proteins in lung tissues of mice in a guanosine treatment group are obviouslylower than those in an asthma model group. Therefore, the invention provides application of guanosine in preparation of a p38 MAPK inhibitor, a p65 NF-kappa B inhibitor, an STAT3 inhibitor or an asthma treatment drug.