Abstract: The Weighted Laguerre Polynomials-Finite Difference Time Domain（WLP-FDTD）method is employed to analyze the transient response of power ground planes in Power Delivery Network. The power ground planes can be regarded as the equivalent 2D circuit networks modeling. Based on this model，the time-domain equations can be obtained. The current and voltage in the equations can be computed with the weighted Laguerre polynomials. According to the orthogonality，the stability condition can be eliminated. Different from the Finite Difference Time Domain method，the WLP-FDTD method is unconditional stable，which separates the time and space variables. This method has fast computing speed in large number of dissection network for computing power ground planes. Simulation results show that the 2D WLP-FDTD method is more efficient than the 2D traditional FDTD in analysis of power ground planes.