Objective To discuss the value of 64-slice spiral CT （MSCT） in diagnosis of gastric stromal tumor （GST）. Methods Thirty-two patients proved GST by surgery and pathology from May 2010 to August 2011 in West China Hospital, Sichuan University were classified by Fletcher malignancy degree classification，the CT features including the location，size，boundary，shape，density，growth pattern，metastases，and enhancement and its relationships to GST malignancy degree were analyzed retrospectively. Results All 32 cases were single lesion，the accuracy of CT in localization was 100%. Nine cases were intra-luminal，10 were extra-luminal，and 13 were both intra- and extra-luminal growth. Nine cases were in low degree group，with diameter＜5cm，round or oval in shape，clear border, homogenous density and enhancement （7/9）；Twenty-three cases were in high degree group，with diameter ≥5cm in 19 cases，irregular in shape and indistinct bourdry （18/23），heterogeneous density （20/23） with necrosis，ulcer was seen in 6 cases. Three cases in high malignance degree group showed pancreas and spleen involvements，2 cases of left diaphragm involvement，1 of omentum metastasis，2 of liver metastases，and 1 of lymph node metastasis. Conclusions MSCT is the optimal method to exam GST，there is correlation between the CT features and malignancy degree，MSCT is helpful for analyzing malignancy degree preoperation.