As a classical partitional clustering algorithm, k-means algorithm is sensitive to initial centroids and may malfunction when dealing with datasets which contain clusters with different scales and densities. To improve the effectiveness of k-means algorithm, an outlier factor based partitional clustering analysis method is presented in this paper. Outlier factor is usually used to indicate the degree of an object to be abnormal in the dataset. For the proposed method, it is used to find the core objects. And then the Must-link constraints is generated to put the neighboring core objects into the same cluster. First, a similar-density-array-based outlier factor is proposed to find the core objects in the dataset. Then the neighboring core objects are distributed into the same sub-cluster. The sub-clusters are treated as the representative objects and these representative objects are then clustered following the process of the traditional k-means algorithm. Finally, the non-core objects are assigned to their nearest clusters, respectively. The experiments are performed on four datasets from UCI Machine Learning Repository and a field dataset from a ball mill pulverizing system. The experimental results verify that the effectiveness of our algorithm is high.