The purpose of this paper is to investigate the effect of age composition on labor force participation rate as well as the change of age-specific labor force participation rate for both males and females in Taiwan. Standardization technique from population method is used to analyze labor force paticipation data obtained from the Taiwan Manpower Utilization Survey from 1979 to 1990. Results from the standardization analyses indicated that the age composition change of from 1979 to 1990 has a leveling effect on the labor force participation rate (LFPR) for both males and females. During the period of time, rate of male labor force participation has been decreased while female labor force participation rate has been increased and then leveling off. Other things being equal, the exact increase and decrease of LFPR for males and females are all more than crude rate. The increase of LFPR of females in Taiwan is main1y due to married women entering the labor market and few of them quit after child birth; while the decrease of LFPR of males is attributed to the facts that the expansion of education opportunities for teenagers and the earIier retirement of the elder male population.