Vector processors play a big role among high performance computing applications such as image processing, machine learning as well as gaming, thus handling vector registers efficiently is important in terms of performance. Calling Convention(CC) is one of the most significant aspects that can affect the execution speed and spills can be avoided if vector registers between procedural calls are controlled and assigned efficiently. In this talk, we will show the design and implementation of RISC-V Vector Calling Convention for C/C++.