∠C=90°,CA=CB,∴△CAB是等腰直角△,
∴∠B=45°,∴△DEB也是等腰直角△,
∴DE=BE,
∵AD是角平分线,∴DC=DE,
∴AC=AE,
∴△DEB周长=DE＋BE＋DB
=DC＋DB＋BE
=CB＋BE
=AE＋EB
=AB
=6㎝,
∴△DEB的周长=6㎝.