We study the luminosity and mass functions of open clusters using the data published by the United States Navel Observatory to figure out the relationships between these functions and the cluster ages. Slope ranges of the luminosity (dlogN/dMv) and mass function (-dlogN/d(log m/m@)) are 0.09-0.52(avg.=0.26, var.=0.01), 0.43-5.49(avg.=1.7, var.=0.63) respectively. These large ranges do not support the mass function is universal, but the function is time dependent. Despite of the poor relationship between the luminosity function and the cluster age, we obtain a good relationship in the mass function. We can understand this good relationship with a viewpoint of stellar evolution. We do age analyses in terms of the metal abundance and the number density of the open clusters. We get the fact that the less metal abundances and the less number densities, the more steep in the slopes of the mass function.