Boron (B) has a good practical application prospect in energetic materials due to its high volumetric and gravimetric heating values. However, the challenge of incomplete combustion inhibited its further application because of the existence of surface boron oxides. Herein, polyethylene glycol (PEG), a kind of oxygen-containing organic matter with an average molecular weight of 2000, was used to modify the B particles at a micron level to improve the combustion performance. The effect of PEG contents on the thermal behavior, heat of combustion, ignition and combustion performance, as well as the combustion intensity of boron powder, was studied. The results showed that the appropriate amount of PEG modification could reduce the ignition temperature of boron powder, increase the degree of oxidation, improve the combustion intensity and heat release. Additionally, the agglomeration behavior of B particles could be alleviated but the improvement diminished with the increase of PEG contents. These results revealed that PEG modification was an efficient strategy to facilitate boron ignition and combustion.