The invention relates to azaindole derivatives, a preparation method and applications thereof in medicine. Specifically, the invention relates to novel derivatives represented by the formula (I), pharmaceutically acceptable salts thereof, pharmaceutical composition containing the derivatives, and a preparation method of the derivatives. The invention also discloses an application of the derivatives, pharmaceutically acceptable salts thereof, or pharmaceutical composition containing the derivative in the preparation of drugs for treating and/or preventing inflammation related diseases, especially Janus kinase 3 (JAK3) inhibitor. The definitions of each substituent in the formula (I) are the same as the definitions in the description.