Abstract: Focused on a lumber stress rating system developed by the authors, a set of anti-interference designs to restrain the effects of different disturbance factors on the system were conducted. These interferences include electric power, transmission channels, electromagnetic radiation, etc. Results showed that the system could display better effects once a new anti-interference method is applied and linear power had better anti-interference effect than switching power. The method of using linear power and adding low-pass filter and isolation transformer with effective grounding measure had the best anti-interference effect.