A method for fixed connection of a solar cell string includes: stacking a back film, a first solder ribbon, a solar cell, a second solder ribbon and a front film to form a solar cell unit; placing a first press and a second press on the front film such that the first press and second press press the front film and back film, and move together with the solar cell unit; and performing a melting-solidification operation while keeping the first press and second press pressing against the front film. A press assembly and a device are also provided to perform the method.