Photon Partial Stereotactic Ablative Boost Radiotherapy (P-SABR) is able to achieve high local control rate while keeping the side effect well tolerated in large NSCLC according to our previous research. Larger tumor volume receiving high BED is also found to achieve higher local control rate. This study aims to further explore whether proton plans can elevate the tumor volume receiving high BED compared with photon plans. Thirty patients with large NSCLC who were previously treated with photon P-SABR were included in this research. All patients underwent repeat planning for intensity-modulated proton beams (2-3 beams) (“IMPT” for short), proton arc beams (10-14 beams to simulate ARC) (“PAT” for short) and photon IMRT, VMAT plans. P-SABR plans were described before. GTV boost was the max volume receiving SABR and the proton plans were created to achieve comparable RBE of GTV margin to photon plans. Dosimetric variables were acquired in both proton and compared photon plans. The majority of dosimetric variables in IMPT and PAT plans were similar, as well as in IMRT and VMAT plans (P>0.5). Compared with VMAT plans, IMPT increased B90 (the ration of volume of BED>90Gy to the in-field tumor), B100, B110 and B120 by 15.05GyE, 42.00GyE and 45.61GyE, respectively (p=0.014, p<0.001, p<0.001 and p<0.001, correspondingly). Both IMPT and PAT plans could achieve higher D75 (volume of the structure receiving RBE >75 GyE), D80, D85 and D90 than photon plans (P<0.05). In addition, despite the maximal RBE and V45 for esophagus were similar (P>0.1), proton plan could significantly reduce the RBE for other OARs, including lungs, heart, spinal cord and mean RBE for esophagus, as well as minimum RBE and D98 for PTV compared with photon plans (P<0.05). In high-dose regions, in spite of the average volume receiving the prescription dose was slightly larger for PAT than for VMAT P-SABR (p=0.084), the average volume receiving >95% of the prescription dose was larger for photon than for proton P-SABR (p <0.001). In low-dose regions, the average volume receiving >50% of the prescription dose and the lung volume receiving >50% of the prescription dose were also larger for photon than for proton P-SABR (p <0.001). While the conformity indexes were similar for proton and photon plans, the average homogeneity index for IMRT, VMAT, IMPT and PAT were 0.71, 0.74, 0.47 and 0.49, respectively. Larger tumor volume receiving high BED and smaller OARs dose were achieved by proton compared with photon plans. Proton P-SABR might increase the local control rate while reduce the side effect for large NSCLC. In large NSCLC, proton could significantly decrease high-dose as well as low-dose regions. PAT plans didn`t have obvious advantage over IMPT in P-SABR for large NSCLC.