Pulsar wind nebula (PWN) Boomerang and the associated supernova remnant (SNR) G106.3+2.7 are among candidates for the ultra-high-energy (UHE) gamma-ray counterparts published by LHAASO. Although the centroid of the extended source, LHAASO J2226+6057, deviates from the pulsar's position by about 0.3 degree, the source partially covers the PWN. Therefore, we cannot totally exclude the possibility that part of the UHE emission comes from the PWN. Indeed, recent gamma-ray analyses by MAGIC and HAWC do separate two sources associated with the PWN and the SNR. Previous studies mainly focus on whether the SNR is a PeVatron, while neglecting the energetic PWN. Here, we explore the possibility of the Boomerang Nebula being a PeVatron candidate by studying its X-ray radiation. By modeling the diffusion of relativistic electrons injected in the PWN, we fit the radial profiles of X-ray surface brightness and photon index. The solution with a magnetic field B = 140 microgauss can well reproduce the observed profiles and implies a severe suppression of IC scattering of electrons. Hence, we propose to introduce a proton component to account for the UHE emission partly originating from the PWN in light of the LHAASO measurement on Crab. In this sense, Boomerang Nebula would be a hadronic PeVatron. Longer detection time of LHAASO may be helpful for verifying the hypothesis.