The invention discloses a method and a system for detecting cyberbullying. The detection method comprises the steps of obtaining a to-be-detected data set; wherein the data set to be detected comprises a plurality of sentence texts of a plurality of users; classifying the to-be-detected data set by adopting a classification model based on a bidirectional recurrent neural network to obtain the probability that each sentence text belongs to network bullets; obtaining sentence texts of which the probability of belonging to the network bullets is greater than a set probability to obtain a first sentence text set; obtaining an attention value of each sentence text in the first sentence text set and an attention value of each user; and according to the attention value of each sentence text in the first sentence text set and the attention value of each user, detecting whether each sentence text has a cyberbullying condition. The method is good in text classification and recognition effect, high in accuracy and low in loss rate.