The concept and physical model of "beam moving" are proposed. For the scheme of angular spectral dispersion, taking the sinusoidally phase-modulated pulse and the linearly chirped pulse for example, the properties of the transverse movement of chirped broadband beam are analyzed theoretically. The effects of the transverse moving speed, the moving cycle and the moving mode on the smoothing of focal spot are discussed in detail. The results show that the linearly chirped pulse could achieve better smoothing effect than the sinusoidally frequency-modulated pulse with the same bandwidth.