AIM Because no ECG lead cable and lead selector is equipped, SYD-4228 Physiology Experiment System can not be used to record and observe ECG. This paper introduces an ECG lead converter/selector designed and implemented by us. METHODS With resistor network and lead input cable, an ECG lead converter/selector was produced. RESULTS As an independent and assistant part of SYD-4228 system, this ECG lead converter/selector can be used to record ECG waveform in animal experiment. CONCLUSION Capable of matching both SYD-4228 system and other ECG recording systems, this ECG lead converter/selector can record ECG waveforms with different lead systems simultaneously. Real-time observation and comparison of waveforms recorded by different lead systems can be available.