A method of establishing a clinical decision support system for SPC risk evaluation among patients with colorectal cancer includes combining cancer characteristics into a characteristic assembly of SPC risk evaluation; obtaining clinical data of first participants to establish a database of SPC risk evaluation; entering the database into a machine learning algorithm; using the machine learning algorithms to establish a SPC risk evaluation model; using a characteristic interpreter to analyze the model; calculating a risk value of each cancer characteristic; presenting the risk values in graphics to establish a clinical decision support system; obtaining clinical data of second participants and inputting same into the clinical decision support system; using the machine learning algorithm for comparison and analysis; predicting risk for SPC; calculating a risk value of each cancer characteristic; presenting the risk values on the clinical decision support system; giving suggestions of decreasing risk; and monitoring changes of the risk.