Considering　the　problem　of　measuring　the　peak　junction　temperature　of　a　double-chip　module　with　temperature　inhomogeneity,　we　use　a　double-chip　parallel　model　to　analyze　peak　junction　temperature　measurement　error　for　the　traditional　electrical　method.　An　improved　test　method　is　proposed　that　is　based　on　the　small　current–voltage　drop　method—specifically　the　dual　current　test　method　employing　an　extended-dimension　calibration　curve　library.　This　method　realizes　a　match　of　the　calibration　current　with　the　test　current　by　expanding　the　dimension　database,　eliminates　errors　of　temperature　measurements,　and　finally　obtains　the　peak　junction　temperature　of　the　module.　The　measurement　result　is　close　to　the　set　temperature　of　the　model,　thereby　verifying　its　accuracy.