Electrospun scaffolds have been widely used in tissue engineering, particularly, bioceramics such as calcium silicate (CSH) composite electrospun scaffolds have shown excellent bioactivity by releasing SiO₃^2- ions during the degradation of calcium silicate in composite electrospun scaffolds, which are bioactive in stimulating angiogenesis. However, the effective ion concentration is in a narrow range from 0.79 to 1.8 μg/mL. Therefore, it is of great significance for tissue engineering applications to accurately control the ion release concentration of the calcium silicate composite scaffolds, so that the ions released from materials can remain in the effective concentration range for a long time. In this study, we prepared a variety of scaffolds with calcium silicate composite electrospun by adjusting pore size of electrospun scaffolds and controlling the location of calcium silicate nanowires inside the scaffolds, and compared ions release behavior and bioactivity in promoting proliferation of human umbilical vein endothelial cells in vitro. The results showed that, due to the hydrophobicity of polymers and limited diffusion of small pore size, electrospun scaffolds with small pore size by mixed-electrospinning or electrospinning-electrospraying calcium silicate composite displayed slow-release behavior of SiO₃^2- ions. In vitro cell experiments showed that the electrospun scaffolds with slow ions release promoted the proliferation of human umbilical vein endothelial cells, indicating that the bioactivity of the composite scaffolds could be regulated by adjusting ions release behavior to obtain optimal bioactivity for tissue engineering applications.