Petrea volubilis

Agree

can anyone tell me how to propagate it?

Try this (from American Hort. Soc. Plant Propagation book): semi-ripe cuttings in summer with bottom heat of 64ð. Simple or air layer in late winter. Supposedly easy.

In warmer climates they won't need bottom heat and you can try any time from spring thru to early autumn. Semi hardwood cuttings, below a node, and above a visible new leaf point. Rooting hormone helps. Remove or trim leaves, put somewhere with humidity like pot with plastic cover, plastic box etc.
You can also propagate from seed but they are slow growing that way.