This paper uses Gaussian interval type-2 fuzzy set theory on historical traffic volume data processing to obtain a 24-hour prediction of traffic volume with high precision.A K-means clustering method is used in this paper to get 5 minutes traffic volume variation as input data for the Gaussian interval type-2 fuzzy sets which can reflect the distribution of historical traffic volume in one statistical period.Moreover,the cluster with the largest collection of data obtained by K-means clustering method is calculated to get the key parameters of type-2 fuzzy sets,mean and standard deviation of the Gaussian membership function.Using the range of data as the input of Gaussian interval type-2 fuzzy sets leads to the range of traffic volume forecasting output with the ability of describing the possible range of the traffic volume as well as the traffic volume prediction data with high accuracy.The simulation results show that the average relative error is reduced to 8％ based on the combined K-means Gaussian interval type-2 fuzzy sets forecasting method.The fluctuation range in terms of an upper and a lower forecasting traffic volume completely envelopes the actual traffic volume and reproduces the fluctuation range of traffic flow.