This paper focuses on the multiple source, multiple destination network tomography problem. The main contributions are as follows. First, the performance stable delay difference measured by the back-to-back packet pair with different size is used firstly as path metrics to identify the topology. Second, this paper proposes a novel probing meathead to infer the hop count of the shared path for each 1-by-2 component and each 2-by-1 component. Third, with the novel methodology, we firstly resolve the key problem of routing topology identification by multiple sources network tomography. The accuracy and efficiency of methodology is validated by the simulation results.