hi guys, just want to ask if its true that attack speed bonus from armor sets will dec skill cd

Cooldown of physicals skills is counted from your Attack speed....
So Higher Attack speed means lower CDs.
Attack speed bonuses from armor sets provide higher attack speed so answer for your question is YES

tnx a lot.

Yes, but it's not incredibly much, for example you have mj light set and you put dc light set, you will barely see the diff in atk speed.

It does influence, but not much. To observe it, you need a good difference, such as with haste and dance of fury and without.