The spectral interference between two white-light continuum beams is adopted to measure the Gouy phase shift of focused femtosecond laser pulses near the lens focus. From the spectral interference signal, the relative phase is extracted by the Fourier transform method. The beam waist of the laser pulses after the focusing lens is measured by imaging method. According to the beam radius, the curves of nonlinear fitting are drawn, and fit the data of experiments very well. The Gouy phase shift at the positions of 1 mm before and after the focal spot is presented.