A method of using a simulation software to generate a circuit layout, the method comprising: (A) determining a plurality of blocks on a circuit board, wherein each block of the plurality of blocks includes an operating space and a reserved space; (B) determining a size of the reserved space of each block of the plurality of blocks according to at least one specific condition;(C) determining whether to adjust the size of the reserved space of each block of the plurality of blocks according to at least one determining condition; and (D) when it is determined not to adjust the size of the reserved space in step (C), generating the circuit layout according to the size of the reserved space of each block of the plurality of blocks determined in step (B).