Value of the Data •The data in this article reveal the in-situ reaction steps (especially high temperature reactions) between titanium and air under laser irradiation, which help to better understand the laser surface modification process of titanium in air. •The data in this article will benefit researchers who need detailed in-situ reaction data on laser surface modification of titanium under air, or those who apply surface modification strategies for decoration or medical applications, or even those who investigate titanium and its alloys under laser-based additive manufacturing processes. •These data present a technique for investigating in-situ interactions, such as laser heating induced chemical reactions or phase changes. This technique can also be used for insights of in-situ interactions of other reaction systems, i.e. the sintering process of titanium and aluminium. Besides, according to the titanium-air interaction steps revealed by the data, through adjusting the laser parameters, TiN/TiO2 layer with varying thickness can be obtained. •In addition, these data will be beneficial for improved modeling data of the titanium-air interactions under laser irradiation.