Interface　creep　cracking　is　very　common　to　be　seen　in　various　kinds　of　welded　components　which　are　used　widely　in　engineering　practice.　In　the　present　paper,　the　interface　creep　crack　tip　field　by　considering　material　mismatch　effect　is　studied.　The　interface　creep　crack　is　found　to　be　close　to　the　HRR　field　which　can　produce　the　faster　creep　crack　growth　rate.　A　material　mismatch　constraint　parameter　is　proposed　based　on　the　validation　of　the　local　mismatch　effect　on　the　interface　creep　crack　tip　field　which　also　maintains　the　self-similarity.　An　averaged　material　mismatch　constraint　M*avg　is　presented　to　represent　the　material　mismatch　constraint　effect.　It　reveals　that　the　material　mismatch　constraint　effect　for　interface　creep　crack　decreases　with　the　increase　of　the　local　mismatch　factor.　The　physical　meaning　of　the　material　mismatch　constraint　effect　for　the　interface　creep　crack　and　its　future　application　to　engineering　failure　analysis　is　also　discussed　and　presented.