The present invention discloses a device for solid-state fluidization mining of seabed shallow layer non-diagenetic natural gas hydrates. The device comprises a hydraulic jet nozzle set, a coiled tubing, a hydrate collecting ship arranged on the sea surface, a transfer station arranged in sea water and a riser arranged in a seabed surface layer. A guide seat is arranged in the riser. The hydraulic jet nozzle set is arranged in the guide seat. A delivery pipe connected with the transfer station sleeves a nozzle body. An opening is formed in a position where the delivery pipe is in contact with the nozzle body. The transfer station is connected with the hydrate collecting ship. The present invention further discloses a method for collecting seabed shallow layer non-diagenetic hydrates.