This paper proposes an efficient method for simulating the radiated immunity of printed circuit board (PCB) with arbitrarily oriented traces. Existing methods usually deal with plane wave excited PCB with simple configuration, for which a SPICE model can be analytically derived. Nevertheless, it is difficult to analytically develop a SPICE model for a PCB whose traces are arbitrarily oriented. In this work, traces of a PCB are divided into small segments. SPICE model of the PCB is obtained by connecting equivalent circuits of all segments. Meanwhile, the incident field is converted to distributed current and voltage sources in the SPICE model. Radiated immunity of the PCB is then analyzed using SPICE. Since it is challenging to analyze all traces of the PCB simultaneously, uncoupled traces are individually simulated. Numerical examples are presented to illustrate the advantages of the proposed method. It is shown that the proposed method is about 17 times faster than a full wave analysis method.