A spatial carrier phase detection technology based on deflection angle will be introduced in order to achieve dynamic phase simply and quickly in the measurement of digital speckle interference. Firstly, deflecting mirror was used to realize space carrier. Interference optical field was formed between object and deflection reference beams, as well as the information of carrier recorded. Then, three adjacent pixels on the CCD array were calculated to obtain interference phase information of the optical field. Finally, fast phase detection was implemented through a single speckle interference image. The method saves calculation times, simplifies the structure of the measuring system as well as algorithms, besides, and achieves the goal of fast phase detection compared with traditional phase detection technology.