The invention discloses an all toluene solvent type polyurethane resin and a preparation method thereof. The all toluene solvent type polyurethane resin prepared by the method of the invention comprises the following components in percentage by weight: 34%-36% of polyurethane, 64%-66% of toluene, and other components are not contained. Thus, the toluene can be recovered by utilizing an active carbon toluene recovery system, thereby overcoming the defect that because the solvent type polyurethane resin in the current market contains various solvent combinations rather than a single solvent, the toluene can not be recovered by the active carbon toluene recovery system, improving the economic benefit and being favorable for environment protection.