Abstract: The physical unclonable functions(PUFs) are getting more applications in information security. However, as a typical strong PUF, the arbiter PUF has deterministic logic, so adversaries could use model attacks to break it. On the other hand, although weak PUFs are immune to model attacks, they cannot provide as many challenge-response pairs as arbiter PUFs. A nondeterministic logic based arbiter PUF was proposed. By combining the arbiter PUF with the weak PUF, partial Boolean relations within the proposed PUF were configured by the nondeterministic outputs of the weak PUF, so its security against model attacks is effectively improved. Meanwhile, experiments in FPGA also show the proposed PUF has good randomness 50.6% and stability 94.5%.