Since the treatment modality and dose are still under exploratory stage, we propose to conduct a Phase I study determining the maximum tolerated dose of CyberKnife SBRT on dose escalation for the treatment of locally advanced pancreatic tumor based on a 5 fractions treatment regimen. A prescription dose of 35-47.5 Gy in five fractions was chosen, with an equivalent to the traditional dose of 2 Gy in 25-39 fractions of BED10. And this is assumed to be the safe and effective dose for unresectable pancreatic cancer patients.