In　the　inductor　design　of　multi-phase　interleaved　voltage　regulator　module　(VRM),　inductor　coupling　scheme　and　its　design　had　become　an　important　measurement　to　better　trade-off　the　static　and　transient　responses.　With　the　introduction　of　dynamic　and　static　inductances　in　the　circuit　model,　an　air-gap　design　guideline　is　proposed　on　air-gap　design　so　that　the　design　engineers　could　obtain　intuitional　and　clear　understanding　of　how　to　achieve　both　static　and　dynamic　performances.　Practical　designs　and　tests　in　a　two-phase　VRM　with　different　air-gap　designs　are　performed　to　verify　the　practicality　and　easiness　of　air-gap　design　guideline.