Nowadays, surgery still remains the mainstay treatment for gastrointestinal stromal tumor (GIST). Nevertheless, some GIST patients have also experienced tumor recurrence/metastasis even with R0 resection. Meanwhile, the prognosis of GIST has been dramatically improved after targeted drug imatinib used in clinical practice for GIST, but tumor recurrence/metastasis still occurred in some patients with high-risk when adjuvant treatment course ended, as such, the 2008 modified NIH criterion, which is used to guide the adjuvant treatment of GIST, still has shortcomings. This criterion can not accurately predict the postoperative recurrence probability and also fails to achieve the purpose of individualized treatment, especially for those patients with high mitotic index who may experience insufficient treatment. Therefore, some domestic and foreign scholars realize that some high-risk GIST lesions with high mitotic index exhibit higher malignant biological behavior, namely highest risk GIST, which is easier to present tumor recurrence/metastasis. The appropriate classification criteria and treatment course are still needed to further exploration.