Lignin nanospheres/poly(vinyl alcohol) (LNS/PVA) nanocomposite films were prepared through solvent casting approach. Compared with lignin/PVA blend film, LNS could be evenly dispersed in PVA matrix, and the nanocomposite films did not generate macroscopic phase separation. Maximum decomposition temperature (Tmax) and glass transition temperature (Tg) of pure PVA film were 264.7 and 104.2 °C, while the Tmax and Tg of the nanocomposite film containing 1 wt % LNS increased to 272.1 and 116.8 °C, respectively. Moreover, with increasing of LNS con...