Realization of strong correlation effect in topological materials is very rare due to lack of ideal systems. In this Rapid Communication, we present the magnetotransport properties of a correlated nodal-line semimetal YbCdGe. A valence fluctuating state has been observed through magnetic susceptibility and specific heat data. This compound shows an extremely large, nonsaturating transverse magnetoresistance (1.14×103% at 3 K and 12 T). The cusplike magnetoconductivity at low magnetic field indicates the presence of weak antilocalization. The origin of this phenomenon is further supported from the direction dependent transport measurements. Magnetic field-induced metal-semiconductor-like crossover and a plateau in resistivity are observed at low temperature which are common features of topological semimetals. Hall measurement and electronic band-structure calculation suggest that YbCdGe is a topological nodal-line semimetal with higher carrier (hole) density than a typical Dirac/Weyl semimetal. © 2019 American Physical Society.