A new method for respective determination of Pb,Cu and Ca in a propellant sample was proposed by flame atomic absorption spectrometry with the microwave assisted digestion to the sample digested by HNO₃. The results of determining Pb, Cu and Ca in the propellant samples, show that the RSDs(relative standard deviations) are in the range of 1.13%~3.23%(n=5) and the recovery is 99.38%~100.60%. The method is simple, rapid and highly accurate.