Abstract: A POST(Power-on Self Test)method of microprocessor system is developed in aeroengine FADEC(Full Authority Digital Electronic Control).The methods of fault detection for RAM memory are investigated and the experiment shows that the methods can detect accurately faults of RAM memory.The fault detection and correction method of Hamming coding in the aeroengine FADEC system is researched.The experiments show that one-fold error of information transference can be detected and corrected accurately by Hamming coding,but two-fold error only can be detected