Help me about system switch control ladder light?
To achieve your goal you will either need some DPDT switches or an "inverter" switch, I don't really know the English word for that.







simulate this circuit &ndash; Schematic created using CircuitLab

Above you can see a DPDT switch wired as an "inverter" switch. Either A is connected to 0, and B to 1, or A is connected to 1 and B to 0. You can add as many inverters as you want between the SPDT switches of your schematic, if the light is on, i.e. there is a path for the hot wire to arrive at the lamp, changing the state of any inverter in the path will break it, and conversely if there is no path changing the state of an inverter will make it.

Inverters were widely used some years ago, nowadays the trend is using push buttons and a latching relay: you wire all your push buttons in parallel, when you press any of them the relay toggles its state.