The invention relates to a natural gas liquefaction device and discloses a natural gas liquefaction device and method adopting a double-compressor two-stage compressed mixed refrigerant for refrigeration. The device comprises one-stage mixed refrigerant compressors, a first cooler, a second cooler, gas-liquid separators, a liquid pump and plate-fin heat exchangers. According to the natural gas liquefaction device and method, natural gas is liquefied through multi-stage refrigeration, heat exchange curves of hot and cold streams are better matched in the whole process, and the consumption of the mixed refrigerant is effectively reduced; double-compressor two-stage compression is adopted during compression of the mixed refrigerant, the volume ratio of the two one-stage mixed refrigerant compressors can be adjusted according to different working conditions, the power consumption can be appropriately reduced, and the selection flexibility of the one-stage mixed refrigerant compressors is better; gas-liquid separation is realized during compression, a separated liquid-phase stream does not participate in the subsequent compression process, and the power consumption of subsequent gas compression is effectively reduced.