Energy-efficient nanosoldering technology for realizing connections at the nanoscale is a long-sought-after goal for constructing advanced optoelectronic nanodevices. However, the ability to achieve noncontact handling, low power consumption, and targeted nanosoldering remains a challenge. In this work, we demonstrate a method of targeted photothermal-induced nanosoldering of silver nanowires, which uses Au80Sn20 alloy nanowires as the nanosolder and a 532 nm continuous wave laser as the heat source. The required power for fusing the Au80Sn20 solder is reduced by a factor of 55 compared to the previously demonstrated Ag self-nanosolder case. Construction of a few typical nanostructures (including "X"-, "Y"-, and "-"-shaped junctions) is achieved with this method. Besides its low power consumption, it also provides advantages including noncontact and targeted soldering, thereby introducing new avenues for fabricating complex nanostructures and advanced functional nanodevices.