Abstract: Objective To explore the effectiveness of helical tomography on locally advanced pancreatic cancer (LAPC), and analyze its prognostic factors. Methods Clinical data of 20 patients (13 males, 7 females; Md age of 56 years) with locally advanced pancreatic cancer who underwent helical tomotherapy without surgery were retrospectively reviewed from Jan. 2012 to Dec. 2015 in our hospital. The short-term effectiveness and long-term survival were observed. Kaplan Meier analysis and Cox regression model were used for univariate and multivariate analysis to determine the prognostic factors. Results Proportions of malignancies located in head of pancreas and body/tail of pancreas were 62.5% and 37.5% respectively (P< 0.05). CA 19-9 levels in 53.8% of patients decreased after treatment. The pain relief rate was 72.7% (8/11). The one-year survival rates and 2-year survival rates were 40% and 10%. Multivariate analysis indicated that tumor location and Karnofsky performance status (KPS) were independent predictors for overall survival. Grade Ⅲ hematologic toxicity occured in one case and no grade Ⅲ or Ⅳgastrointestinal toxicity occurred. Conclusion Helical tomotherapy is an effective treatment for locally advanced pancreatic cancer with less toxicity. Our study shows that the head and body/tail of the pancreas probably has different radiotherapy sensitivity, but this conclusion need to be further confirmed.