[Purpose/significance] The paper regards the rumor information and the corresponding dispelling rumor information as a pair of heterogeneous information spreading in microblog, and uses Principal Component Analysis (PCA) to study comprehensive influence of the rumour and counter-rumour. [Method/process] First, constructing the evaluation index system of comprehensive influence of the rumour and counter-rumour, including figure dimensions, subject dimension and network dimension; Then, conducting the principal component analysis based on the real rumour and counter-rumour information data of microblog, separately getting the six principal components of comprehensive influence of the rumour and counter-rumour, and putting forward comprehensive influence model on the basis of the above. [Result/conclusion] The model is used to measure the influence of rumors and counter-rumour of specific public opinion case, and the validity of the model is verified by combining the real evolution results of the case.