Hello I'm just curious about the reason to why the overhead bin was most commonly being put on top of our seat and head.
Because it is the most efficient use of space.
Due to the physics, specifically the way pressure differential is spread in a container as stress, a perfectly circular tube is the best shape for the body of an airplane, and a rectangular box is way, way, worse. Modern airlines have an oval cross-section, but it is still a lot closer to a tube than a box.
The question is than how do you allocate the space inside a tube. The widest floor area is in the middle vertically, so that is where the passengers go. Now we have roughly one to two meters of vertical space both above and below the passenger deck, not high enough to accommodate people but enough for cargo and storage.
Naturally you would want the heavy cargo to go below, and passenger storage to go above, for logistic reasons. Putting them on the same deck as the cabin would reduce the usable floor area for putting seats. You'd want maximum floor area to place the maximum number of passenger seats to increased revenue on the same flight.
People need to store their carry-on luggage somewhere. The space above passengers' heads is usable space. So it's only logical to store carry-on luggage in the space above passengers' heads.
Well, why it's not below the sit? I mean, if the plane fall wouldn't it lower the risk of someone get hit with heavy stuff on their head??
Cargo is already stored underneath the seats. Checked baggage is stored in the cargo hold underneath the passenger compartment. Small carry-on items can already be stowed directly underneath the seats. There's no additional room for baggage underneath the seats.
Removing the overhead compartments would reduce the risk of someone getting hit in the head by falling baggage, but as far as I know, these injuries are already rare.
You also write:
I just wondering if the overhead bin can be removed. We can create escape system like jet fighter pilots in the event of plane fall.
No, it's not feasible to create a fighter-style escape system. See: Could ejector seats save lives in commercial aircraft?