The invention belongs to the technical field of text classification and provides a method and system for judging the text similarity. The method and system for judging the text similarity are used forovercoming the defects which exist in three kinds of text similarity judgement algorithms in the prior art separately. The method comprises the steps 1, a vector space model is established and subjected to text quantization to form a processible object; 2, a Siamese network is used for establishing a text semantic similarity extraction model, in the Siamese network, a text semantic extraction network and a similarity judgement network are in series connection, and meanwhile optimization is conducted at the sample training stage; 3, based on semantic characteristic expression of samples at thetraining stage, a text similarity calculation function of the included angle cosine based on characteristic vectors and a final loss function are established; 4, two pieces of text to be tested are input, after the text to be tested is subjected to semantic characteristic extraction based on the Siamese network, the cosine included angle distance of the two vectors is calculated, a threshold value is set, and when the cosine included angle distance of the two vectors is larger than the threshold value, the similarity is judged, otherwise, the dissimilarity is judged.