In recent years, it’s a hot topic to study surface treatment technologies on cast iron discs, while traditional brake couples still occupy a large market share, so it is necessary to study the behavior of them. This study focuses on brake judder which is one of the most annoying comfort-complaints while employing brake applications in automobiles. As one of the major components of the brake corner assembly, brake discs play a vital important role in brake judder issues, especially the discs’ geometry, such as DTV (disc thickness variation) and LRO (lateral run-out). According to the statistics of most brake judder complaints from the market, it is already learnt that the majority of the judder cases happened with larger DTV growth compared to the brand-new discs. Therefore, the key countermeasure to decrease the contributions of discs to brake judder is to reduce the DTV growth. Various kinds of factors could lead to inhomogeneous wear of discs and thus generate larger DTV growth, such as larger MLRO (mounting lateral runout), higher caliper drag torque as well as more aggressive friction materials. The homogeneity of both disc geometry and material influences the DTV growth. Normally, the geometry homogeneity could be guaranteed through robust and precise machine and tolerances inspection on line. However, the material homogeneity is difficult to be defined and inspected with few quantitative control standard and inspection method. Therefore, the influence of the material homogeneity to brake judder is generally ignored in production. So, it’s valuable to study how the disc material homogeneity influences the DTV growth. In this paper, first the disc material homogeneity was defined by microstructure and graphite contents. Then the correlation coefficient between disc material homogeneity and the DTV growth was calculated. Based on the study above, the criteria were established to instruct the design of casting process. Combined with the known correlation between DTV and brake judder, the relationship between disc material homogeneity and brake judder is derived accordingly.