The spot dancing of laser beam in a turbulent atmosphere was studied experimentally with a detector array system. The system has advantages over the imaging system, i.e., wide dynamic range and high sampling rate. The results of groud-based transmission experiments show that the spot dancing is a little larger in the vertical direction than in the horizontal direction. Under strong turbulence condition in clear weather the spot dancing coincides quantitatively with theoretical prediction, and its time variation is similar to that of the light scintillation, but they can be much different from each other under other conditions. Up to one thousand hertz the power spectrum of the spot dancing can be well fitted by power laws in three frequency ranges, and the exponents are about -1.2, -2.4, and -4.8 respectively.