For those who have installed vinyl flooring before , replacing your old parquet floor tiles :

Vinyl flooring need a flat surface. If the existing parquet is already flat, then can lay on top. If not, u can either remove the parquet or sand down the existing parquet. Otherwise, u will see a lot of undulations later.

Thank you for your reply, acbc ! I was thinking the same, to just lay on top .. But my area is prone to termites (white ants) . I usually DIY white ants treatment on my attic, and wood areas in the house ..

So not sure will it be a breeding ground for the termites in the parquet , if I just lay on top?

I think is better u remove, as I dint remove.
Now go uneven, walk on it got hollow sound.

if lay on top, how to settle the door gap height problem?

Best to level off the underlying cement. Otherwise, since the vinyl covers the parquet, you may not be able to detect termites as their telltale dust trails will be underneath the vinyl floor. If they attack things on top like cabinets or doors one can see.. but if all hidden how to see?

CNY new year, new flooring..hehe.