The invention relates to the field of agricultural machinery, in particular to a liquid fertilizer applying device and method with soil turning and refilling functions. The liquid fertilizer applying device comprises a flat cart, wherein a rectangular receding groove is formed in the flat cart, the liquid fertilizer applying device further comprises a controller, a digging and filling mechanism, a stirring mechanism and a spraying mechanism, the digging and filling mechanism comprises an outer cylinder, an arc-shaped digging plate and a rotating assembly, the stirring mechanism comprises an inner cylinder and a stirring assembly, the spraying mechanism comprises a conical containing box, a conveying assembly, an extrusion assembly and a plurality of atomization nozzles, and the rotating assembly and the conveying assembly are electrically connected with the controller. According to the liquid fertilizer applying device and method with the soil turning and refilling functions, liquid fertilizer can be uniformly mixed with soil, fertilizer application is more uniform, meanwhile, dug soil can be completely conveyed into the device, residues are prevented, the improvement of the soil turning efficiency is facilitated, the dug soil can be thoroughly refined, and the soil turning effect is improved.