I got flashing CEL this morning, when I started my car. Then I recycle the ECU and started the engine again, the flashing CEL is gone. I usually got a steady CEL light but this is my first time I got the flashing CEL. Anyone know what is the different between steady CEL and flashing CEL?

A flashing CEL means there is a misfire being detected in real time, while a steady CEL means a problem has been detected by the ECU at some point in the past and a code stored. The flashing CEL is more urgent and should be attended to right away, resetting the ECU is no fix even if it temporarily clears the light.
You need to find out what caused the misfire to occur, start by checking your plugs and coils for any signs of fouling/arcing.
This assumes your car is stock, if you have mods they may have something to do with it.

either way, ushould bring it to the dealer if u dont have a lot of mods and have them pull the code, it'll be the safest way to ensure no problems in the future.