We have studied experimentally the intensity characteristic of the fifth-order harmonic radiation produced by two coherent femtosecond laser pulses with a changeable relative phase.The intensities of the harmonic generation are found to increase with the coherent degree.The maximum intensity of harmonics exhibits an asymmetric characteristic with respect to the point where the two components are superposed completely.This fact verifies the influence of deformation of the merged beam on the harmonic generation.Meanwhile,we have carried out some fundamental experiments,based on the theory of stimulated emission.