Continuous casting is a promising technology for massive production of multi-crystalline silicon. Solidification structure has an important influence on the conversion efficiency of solar cells. However, there is no relevant research on the effect of different parameters on the solidification structure during continuous casting, using the continuous casting apparatus of multi-crystalline silicon firstly designed in our research. In order to improve this situation, numerical and experimental works were carried out. The results indicate that the area of columnar grain zone perpendicular to the billet bottom is mainly affected by the casting speed, the pouring temperature and the bottom block cooling intensity. Moreover, the grain size is mainly affected by the density of nuclei and the nucleation undercooling. (C) 2019 Published by Elsevier Ltd.