Predicting aggressive Crohn's disease is crucial for determining therapeutic strategies. We aimed to develop a prognostic model to predict complications leading to surgery within 1 year after diagnosis of Crohn's disease and to create a nomogram to facilitate clinical decision-making. This is a retrospective study. This study was conducted from January, 2012, to December, 2016, in a single tertiary inflammatory bowel disease center. Patients diagnosed with Crohn's disease showing B1 behavior according to Montreal classification were included. We measured the occurrence of complications that would ultimately lead to surgery, including severe gastrointestinal bleeding (Glasgow-Blatchford score≥6), stenosis, and perforations, confirmed by endoscopy, computed tomography scan, or/and interventional radiology. The mean follow-up period was 54 months (standard deviation 13 months). Of the 614 eligible patients, 13.5% developed complications leading to surgery. Multivariable logistic regression revealed the independent predictors of early-onset complications to be age (adjusted odds ratio [aOR] per 10-year increase in age=0.4; 95% confidence intervals [95% CI]:0.2-0.8, P=0.004), disease duration (aOR =2.7, 95% CI:1.9-3.8, P<0.001), perianal disease (aOR=16.0, 95% CI: 4.3-59.9, P<0.001), previous surgery (aOR=3.7, 95% CI:1.6-8.6, P=0.003), and extraintestinal manifestations (aOR=7.6, 95% CI: 2.3-24.9, P=0.001). The specificity and sensitivity of the prognostic model were 88.3% (95% CI: 84.8%-91.2%), and 96.6% (95% CI: 88.1%-99.6%), respectively, and the area under the curve was 0.97 (95% CI: 0.95-0.98). This model was validated with good discrimination and excellent calibration using the Hosmer-Lemeshow goodness-of-fit test. A nomogram was created to facilitate clinical bedside practice. This was a retrospective design and included a small sample size from one center. Our validated prognostic model effectively predicted early-onset complications leading to surgery and screened aggressive Crohn's disease, which will enable physicians to customize therapeutic strategies and monitor disease. See Video Abstract at http://links.lww.com/DCR/B442.Registered at Chinese Clinical Trial Registry (ChiCTR1900025751).