A double scanning laser speckle interrferometric experiment was designed to investigate the movement of nano magnetic particle clusters around 100 nm. In experiments, the interferometric fringes were used as the scales of speckle motion to measure the movement of nano magnetic particles in a magnetic flow field to avoid large computation and the precision dependent on the subpixel searching algorithm. Furthermore, the phase delay scanning was used to compensate the additional phase change caused by a transverse scanning to improve the space resolution of dynamic spackle measurement. An experiment was performed on the nano magnetic clusters with the sizes of 30-100 μm. The experimental results show that the movement of the magnetic particles in the cluster is nonuniform motion and a turbulent flow with an average speed of 6.93 mm/s, which are caused by the nonlinear changes of magnetic field, the collision and aggregation between the particles, and some unknown complex factors.Moreover, the method can meet the different measuring requirements for easy precision adjustment by changing fringe spaces.