Laser spot echo imaging detection experiment is carried out on a 1 km transmission path in turbulent atmosphere under typical weather conditions using a red laser, a 3M microcrystalline prism array reflector, and a telephoto high speed CCD. Scintilloscope and atmospheric coherence meter are used for real-time monitoring of turbulence parameters. Intensity of the laser spot image is statistically analyzed. Spatial correlation coefficients of the scintillation index and the light intensity fluctuation in different positions and different aperture ranges are obtained, and the ideal point scintillation index of the center point of the spot is obtained with the fitting method. The turbulent refractive index struture constant calculated by scintillation index is compared with the real-time monitoring data, and the results show that the turbulent refractive index structure constant obtained by this method is in good agreement with the measured value of the laser scintillator. The laser imaging detection method of the reentry path can easily ensure the paraxial approximation conditions, which is theoretically more realistic. This system can be used not only to observe the complete far-field laser spot affected by atmospheric turbulence, but also to develop a new detection technology of single-ended atmospheric optical turbulence parameter imaging through quantitative modeling.