The Tethys originally refers to the ancient ocean in the southern margin of Eurasia, but gradually extends to a series of ancient oceans from the Proterozoic, Paleozoic to Mesozoic, such as the Proto- Tethys, the Paleo- Tethys and the Neo- Tethys, in which different oceans overlap in time. Now what is stretching between Gondwana (Antarctica) and Eurasia is the Indian Ocean, the successor to the Neo- Tethys, namely the “Holo- Tethys”. The extension of this concept literally reflects the continuous relationship between the Indian Ocean and the Tethyan tectonic domain, which is helpful to understand the evolution process of the Tethyan tectonic domain more intuitively by studying the present process. In this paper, the tectonic evolution and magmatic processes of the Indian Ocean are summarized according to the time series, and the key seafloor spreading events at 155 Ma, 120 Ma, 90~84 Ma, 76 Ma, 65 Ma, 52 Ma, 45 Ma and 38 Ma are identified. These spreading events will provide references for the evolution of the Neo- Tethyan tectonic domain. The width of Neo- Tethys Ocean may culminate around 155 Ma, while 90 Ma may indicate the subduction of the mid- ocean ridge of Neo- Tethys. 76~52 Ma is the time of initial collision and the main collision between African- Arab and Eurasia (ie,the western Neo- Tethys was closed), while 65~45 Ma is time for the initial collision and the main collision between India and Eurasia (ie,the central Neo- Tethys was closed). And the eastern part of Neo- Tethys north of Australia may initiate its subduction at 38 Ma. The study of Indian Ocean spreading history provides a reference for understanding the extinction of the Neo- Tethys Ocean and the process of the India- Asia collision. From the perspective of the “rear” Indian Ocean, the evolution process of the “front” Tethyan tectonic domain can be more clearly understood. The movement of plates and the mechanism of plate tectonics can be further constrained by the study of generalized Tethyan tectonic domain.