The invention discloses an automatic soil scattering machine for sowing of floating seedling raising. The automatic soil scattering machine structurally comprises a soil scattering machine body, a soil material storage bucket, a discharge port, a support plate rack, a base, a uniform soil scattering mechanism, shifting rollers, back-and-forth tracks, protecting covers, handles, a power roller, a drive belt and driven rollers, wherein the soil material storage bucket is arranged in the soil scattering machine body and connected with the soil scattering machine body by electric welding; the discharge port is formed in a lower port of the soil material storage bucket and forms an integrated forming structure with the soil material storage bucket. The automatic soil scattering machine has thebeneficial effects as follows: by means of the uniform soil scattering mechanism, a soil material can be subjected to vibrational sieving firstly and is sent into a soil scattering cylinder, the condition that cleaning is inconvenient due to blockage of the soil scattering cylinder by the large-particle soil material is prevented, and then the soil material is uniformly scattered on a floating seedling raising tray in a vibrating manner, so that uniformity of soil scattering is improved effectively; meanwhile, a protecting device is arranged, and the service life of the machine is prolonged.