Improvisation is becoming increasingly hot in the organizational and strategic field. Yet, from the improvisation perspective, it is less obvious about the origins of improvisation, the building of improvisation, and the relationship of improvisation and innovation. To answer these questions, this study uses an exploratory longitudinal multiple-case study design. The research setting was the highvelocity environment of the offshore IT outsourcing industry. Our sample consists of two globally recognized Chinese IT service vendors which had several characteristics that fitted our research question. The overall result of our work was a model of the improvisation in offshore IT outsourcing, showing that: (1) Improvisation is really cultivated by culture in offshore IT outsourcing. Uncertainty levels and time pressure, although necessary, is not a sufficient condition for the emergence of improvisation. (2) Taking form improvisation consists of two distinct but interdependent processes of building structural ties (routines, plans and rules)and building relational ties (communication, swift trust), which is in contrast to the isolation approach in the existing improvisation literature. (3) Improvisation, because both structural ties and relational ties promote or restrict information flow and time-consuming, is associated with good or poor innovation performance. The implications of these findings for researchers are discussed.