The present invention relates to the field of pharmaceutical chemistry, and particularly to an aza-benzo[f]azulen derivative (I) and an antitumor effect thereof. Pharmacological tests show that the compound of the present invention has in vitro and in vivo antitumor activities, and can be developed into clinical drugs for treating or controlling diseases such as stomach cancer, lung cancer, liver cancer, breast cancer, colon cancer, prostate cancer, and oral cancer.