其实一直不是很懂乱码后面的原理，有点小猜测

Correct, that is because the stack ("stack" as in assembly language) is overflowed to the screen buffer. The algorithm is still unknown - to be correct, it is not known by this group, as I asked several times; and the algorithm is in fact known, but in its current form - disassembly - it can't be understood.
Basically if we view some data in a different format it looks random.