The invention provides a method and device for predicting telecom traffic. The method comprises the following steps: determining the prediction granulation of the telecom traffic; selecting a historical sample and a prediction sample; respectively calculating the growth rates and the initial values of the telecom traffics of the historical sample and the prediction sample by using a unary linear regression model; calculating the prediction traffics of the historical sample and the prediction sample; reading the actual traffic of the historical sample; and adjusting the second prediction traffic according to the deviation between the traffic of first prediction and the actual traffic to obtain the prediction traffic adjusted by a user. The behavior mode of the user is obtained through analyzing the deviation between the linear prediction value and the actual value in the historical sample, and accordingly, the linear prediction value of future telecom traffic data is adjusted to obtainmore accurate telecom network traffic, thereby providing decision support for the user to plan, organize and manage network more accurately.