Control of molecular dynamics in an intense laser field has been studied by employing the time-dependent wave packet approach. A system of K2 molecule in three states (ground state|X, excited state |B and ionized state|X+) serves as a prototype which interacts with pump-probe laser fields. Interacting with an intense pump field, the excited state |B splits into two substates: | and |. Information of the energies and probability distributions of dresses states | and | can be obtained by analysing the photoelectron spectra (PES) of K2 molecule. Meanwhile, the scheme of selective population of dressed states (SPODS) has been put forward according to the dressed states theory of K2 molecule. It is found that regulating the laser intensity can control the dressed state energies, and altering the laser wavelength can make the high selectivity of the dressed state population readied.