The improvement of digestive cancer survival results in increased morbidity of noncancerous comorbidities. This study aimed at clarifying causes of death (COD) and predicting overall survival (OS) in patients diagnosed with liver cancer, gallbladder cancer, cholangiocarcinoma, and pancreatic cancer. We used the Surveillance, Epidemic, and End Results database to extract information. Nomograms of multivariate Cox regression was used to predict OS of cancer patients. The models were evaluated using the concordance indexes (C-indexes), the receiver operating characteristic curves and calibration curves. Respectively 58,895, 15,324, 30,708, and 109,995 cases with cancer of liver, gallbladder, bile duct or pancreas were retrieved between 2000 and 2020. Approximately 80% deaths occurred within 1 years after cancer diagnosis. Sequence in noncancerous COD proportion was diverse, while diseases of heart always accounted for a great part. Risks of death from most noncancerous COD were significantly higher than that of the cancer-free population. Nomograms were developed by predictors of interest such as age, therapy and TNM stage. The concordance indexes of nomograms were 0.756, 0.729, 0.763, and 0.760 respectively, well-calibrating to the reality. The 0.5-, 1-, and 2-year areas under the receiver operating characteristic curve were about 0.800, indicating good reliability and accuracy. Noncancerous COD accounted for larger part in gallbladder cancer and cholangiocarcinoma. Noncancerous COD showed an upward trend as follow-up time extended and the majorities were diseases of heart, cerebrovascular disease, chronic liver disease and cirrhosis. The novel OS-nomograms can provide personalized prognosis information with satisfactory accuracy.