The top-ranking world-class universities in agricultural science denote those universities which are globally popular with agriculture-related subjects. The paper synthesizes the results of three different ranking scales (NTU, QS and ARWU) of top 50 universities in agriculture subject in 2013. The overlapped parts have been synchronized to derive the following four classifications: A (agricultural universities amalgamated with others to be an agricultural comprehensive university), R (agricultural universities re-named to be a comprehensive university), M (agricultural universities merged into other units to form or to be a part of a comprehensive university) and C (comprehensive university's agricultural colleges or departments all the time). The following conclusions can be drawn: the majority (up to 94%) of these universities are comprehensive ones (combination of R, M and C), and only 6% of them are purely named agricultural universities; merging, renaming and comprehending are the three paths of agricultural universities' development; and to be a world-class university, it is necessary to have more than 9 ESI 1% advantage subjects among the following: Plant and Animal Science, Environmental Science/Ecology, Biology and Biochemistry, Clinical Medicine, Chemistry, Engineering, Agricultural Sciences, Social Sciences/General, Molecular Biology and Genetics, Pharmacology and Toxicology and Geosciences. It would be possible for specialized universities to be world-class universities in their fields by being a major concentration of teaching and research as well as extending other subjects through merging and renaming.