factors on which natural frequncy of a building depands?

Answer 1

Mass distribution and stiffness matrix - same as any other structure.

Do a search on natural frequency. You should run across an equation that looks something like the square root of the spring constant over the mass. Higher spring rates and less mass lead to higher natural frequencies.

You can use an FEA tool to determine a stiffness matrix.

Answer 2

Another obvious factor is height. Some simplified estimates for a given type of structure base the nat. freq. on just the height.