Estimating ages for a large number of giants is of great importance for studying Galactic evolution.In this work,we determine stellar ages and masses for 556007 giants from LAMOST Data Release 5 (DR5)with empirical relations estimated from chemical[C/N]abundance ratios.Our sample reveals the two well-known sequences in the age-[α/M]relation.The high-α sequence is composed of stars older than 8 Gyr and low-α sequence is composed of stars with age ranging from 0 Gyr to 13.8 Gyr.Our sample also shows a flat age-[M/H]relation up until 12 Gyr.We compare these distributions with Galactic Chemical Evolution models for reference.When looking at the spatial distribution of stars in 2 Gyr age bins,we find that young stars are concentrated towards the Galactic plane and older stars extend to higher height above and below the disk.We find a smooth transition of median Galactic height for different age bins,which suggests a strong age-dependence on Galactic scale height.