Abstract: A method is described for accurate measuring of the excess carrier lifetime on a semiconductor sample from the carrier decay after termination of the excitation pulse imposed on the steady-state carrier excitation. The method includes determining a quality of decay parameter using progressing segments in each carrier decay; establishing an accurate lifetime measurement multiparameter domain for experimental variables whereby the quality of decay parameter falls within prescribed limits from the ideal exponential decay value of QD=1; and determining an excess carrier lifetime for the semiconductor sample based on experimental measurement conditions within the domain and the quality of decay value within the predetermined range indicative of an accurate excess carrier lifetime measurement.