The photometric evolution of cluster stars are examined for six synthetic clusters in the age range from 2.4 × 10 6 y r t o 7.6 × 10 8 y r by using the detailed evolutionary model calculation, and their results are compared with the observed integrated absolute magnitude and colors of 47 clusters. The reasonable agreements of the observed photometric parameters with the synthetic evolutionary sequences imply that there is a general form of time-dependent IMF including the noncoeval formation of stars and its detailed function is changed slightly with various environmental conditions of each primordial cloud.