A convex growth interface shape is desired but is usually hard to form during the Bridgman process of CdZnTe crystal due to its low thermal conductivity. In this work, the convex interface shape was first analyzed and the mathematical criterion was determined. Theoretical analysis indicates that a convex interface can form when the derivative of axial temperature gradient (∂2T/∂y2) near the interface is negative. The temperature profiles were then proposed according to the theoretical results, and correlative temperature gradient characteristics were presented. The 90 mm diameter CdZnTe crystal has been grown by VGF technique using the proposed temperature profiles. The experimental result shows the interface shape is always convex throughout the entire growth run, which could make a better CdZnTe single-crystalline yield possible.