Constructing polyproteins consisting of identical tandem repeats of proteins provides an unambiguous method of investigating the mechanical properties of proteins at the single-molecule level using force spectroscopy techniques. Here we report a maleimide-thiol coupling-based facile method of constructing polyproteins for single-molecule force spectroscopy studies on the mechanical properties of proteins. This method allows for the construction of polyproteins in an efficient fashion under room temperature. The resultant thioether bonds are resistant to reduction and make it possible to carry out single-molecule force spectroscopy studies under various redox conditions. This novel method complements existing polyprotein engineering methods and can be easily applied to a wide variety of proteins.