The carrier and spin dynamics in solution-processed PbI2 film on quartz substrate have been systematically studied by transient reflectance (TR) spectroscopy and femtosecond resolved Kerr rotation spectroscopy. The results show that TR spectroscopy includes one band of photo-induced bleach (PB) centered at 502 nm and two bands of photo-induced absorption (PIA) at 487 and 522 nm,which are interpreted by band filling effect and band gap renormalization effect.The Kerr magneto-optical signals excited by left-handed and right-handed circularly polarized light are completely opposite in sign and almost equal in size.With the increase of pump fluence,the Kerr rotation angle and ellipticity increase linearly at first,then slowly,finally reach maximum value,~10 degree and 0.12 per micro,respectively.At the same time,the spin relaxation life decreases a minimum value ~1.6 ps.According to our experimental data,the spin relaxation mechanism in PbI2 thin films is attributed to the Elliott-Yafet process owing to the strong spin-orbit coupling caused by the heavy atom lead.In addition,we find that Kerr effect has a large signal around the band gap, which suggests that the spintronic devices based on PbI2 have high sensitivity around the band gap.These experimental results obtained in this paper are of great significance for exploring the potential applications of PbI2 thin films in spintronic devices.