The initial designed structure of the diameter measuring gauge of filter rod forming machine was too large, so that it could not be installed in the limited space of filter rod forming machine. The structure of the diameter measuring gauge was redesigned in order to overcome the space constraints of filter rod forming machine. Firstly, the redesigning of diameter measuring gauge of KDF2, KDF3 type filter rod forming machine was guided by combining the advantages of the theories of inventive problem solving (TRIZ) and constraints (TOC). Next, through constraints theory, the key contradictions of the initial design were found and the contradictions were eliminated using the inventive problem solving theory. Finally, a feasible innovation design scheme for diameter measuring gauge of filter rod forming machine was achieved, and the product design was successfully completed. In conclusion, reasonable combination of these two theories can obtain innovation design schemes more rapidly.