[Objective] This paper aims to extract valuable information from large amount of complaint texts with the help of Chinese message processing technologies. [Methods] First, we analyzed the characteristics of the complaint texts, and then clustered them by k-means algorithm. Second, we extracted topics from the texts of each category with the LDA model. In the mean time, we calculated the weight of the word of each topic, as well as the mean of document probability distribution. Third, we analyzed topics with the highest means and used the document supporting rates to identify the trending ones. [Results] The document supporting rates of the topics extracted by this study was three times higher than the average ones. [Limitations] We did not investigate the semantic relationship among the topics. [Conclusions] The LDA model is an effective method to detect hot topics of the mobile complaints and indicates some future studies.