Position-resolved microstructure in a single spherulite of iPP is quantitatively studied by synchrotron microfocus wide angle X-ray scattering. The results show that the normal of mother lamellae in a spherulite is aligned mainly perpendicular to the radius, and the subsidiary daughter lamellae are inclined 80.75 degrees with respect to that of the dominant mother lamellae. The crystallinity in the spherulite is in the range of 46%-56%, which is rarely influenced by the crystallization temperature. The ratio between the daughter lamellae and the mother lamellae is 0.18 when iPP crystallizes at 138 degrees C and it decreases to 0.11 as the crystallization temperature is decreased to 130 degrees C. The b-axis and c-axis in the mother lamellae tend to orient perpendicular to the radius direction, and the a-axis prefers to align in the radius direction. (C) 2018 Elsevier Ltd. All rights reserved.