The invention discloses an all-aluminum back-field back silver paste, a preparation method thereof, and an application thereof. The all-aluminum back-field back silver paste comprises the follow materials of, by weight, 10 to 80 parts of specially required silver powder with the purity larger than 99.99%, 0.5 to 5 parts of self-made lead-free main body glass powder, 0 to 3 parts of low-melting-point auxiliary glass powder, 1 to 50 parts of specially required low-melting-point metal powder, 15 to 50 parts of organic binders, and 0.01 to 1 part of organic auxiliary. The all-aluminum back-field back silver paste can be directly printed on an aluminum back-field paste, the considerable welding tensile force and aging tensile force of the all-aluminum back-field back silver paste are guaranteed, a serious electric leakage problem caused by a metal defect generated by the direct contact between silver and a silicon wafer is avoided, therefore, the photoelectric conversion efficiency of a crystalline silicon battery is improved, the width of a back electrode and a printed pattern can be adjusted at will, and therefore, the cost of a back electrode paste is reduced.