Abstract: With widespread recent concern on System-on-Chip (SoC), IP (Intellectual Property) reuse has emerged as a vital and growing business in IC industry.IP protection becomes a crucial task from illegal reuse.In this paper, we introduce a novel watermarking technique for IPP on physical layout design.We improved the watermarking strategy by net composition.The experimental results on IBM-PLACE 2.0 Benchmark Suites show that watermarking embedding probability is improved greatly.