The invention discloses a core assembly pouring device for a cylinder body casting in an automobile engine, comprising a base plate (4), two raiser cores (2), a sprue core (3), sand core assemblies (1) and a locking device (5), wherein the sand core assemblies (1) are connected on the base plate (4) and are locked by the locking device (5), the raiser core (2) and the sprue core (3) are located on the two adjacent sand core assemblies (1) which are clamped on the base plate (4), and the locking device (5) is sleeved and pressed outside the two sand core assemblies (1). By adopting the structure, the sand core of the cylinder body consists of a plurality of sand cores, and each sand core is composed of a plurality of small sand cores, thus reducing the size of each sand core, being beneficial to the forming of the sand cores and reducing casting defects of castings; and meanwhile, the number of the sand core assemblies is two, e.g. one die generates two castings, thus greatly improving production efficiency.