The invention discloses a vehicle forced lane changing decision-making method based on a decision-making tree model. The vehicle forced lane changing decision-making method includes the following steps: firstly, reading related data during vehicle forced parallel lane changing in real time through a sensor; secondly, importing the obtained data into a vehicle forced lane changing decision-making module based on the decision-making tree model, wherein a method for building the module includes the steps of selecting training and testing data, splitting a tree, selecting attribute threshold values, pruning the tree, building the parallel lane changing decision-making tree model based on a weka platform and verifying the accuracy of the decision-making model; finally, forming a decision-making judgment result during vehicle forced lane changing through a decision-making module, and if the decision-making judgment result is that lane changing can not be carried out, giving an alarm in real time to remind a driver of the fact that lane changing can not be carried out. By means of the vehicle forced lane changing decision-making method, negative effects, caused by a complex early-warning algorithm and excessive decision-making judgment rules, on the judgment result are reduced, the accuracy and the reliability of decision-making judgment during vehicle forced lane changing are improved, and the false alarm rate is lowered.