Laser plasma interaction (LPI) have always been a crucial research topic in the ignition phase of inertial confinement fusion (ICF). Over the years, researchers have attempted to use various laser beam smoothing schemes and optimized light source solutions to suppress the development of LPI. Among these, low-coherence laser drivers have recently attracted widespread attention in the fields of laser-plasma physics and laser technology. Recently, a broadband second harmonic laser facility named "Kunwu" has provided a reliable experimental research platform for the LPI process driven by broadband lasers. Aiming at the strong stimulated Brillouin scattering (SBS) and stimulated Raman scattering (SRS) in the LPI process of large-scale low-density plasma, forward scattering and near-forward scattering experiments of C<sub>8</sub>H<sub>8</sub>planar film targets driven by broadband and narrowband lasers under the same conditions were carried out. Based on the "Kunwu" laser facility, two sets of measurement systems have been designed, one centered around fiber-heads and spectrometer, and the other around phototubes and oscilloscope. These systems enable multi-directional precise measurements of scattered light, allowing for a comprehensive analysis of LPI. The main focus is on the comparison of the components and spectral information of the scattering beams for broadband and narrowband lasers, and it is found that the LPI processes driven by broadband and narrowband lasers have significant differences. Additionally, preliminary results indicate that broadband lasers exhibit a stronger penetration capability compared to narrowband lasers. The time to ablation the target and penetrate the plasma were nearly 1 ns ahead, with the transmitted energy increased by nearly an order of magnitude. And after penetrating the plasma, there was a smaller spatial divergence angle. These results have good reference value for better understanding the effect of broadband lasers on LPI.