We study the energy sources, the physical properties of the ejecta and the circumstellar medium (CSM), and the mass-loss history of the progenitor of SN 2017dio, which is a broad-lined Ic (Ic-BL) supernova (SN) having unusual light curves (LCs) and signatures of hydrogen-rich CSM in its early spectrum. We find that the temperature of SN 2017dio began to increase linearly about 20 days after the explosion. We use the 56Ni plus the ejecta–CSM interaction model to fit the LCs of SN 2017dio, finding that the masses of the ejecta, the 56Ni, and the CSM are ∼12.41 M ⊙, ∼0.17 M ⊙, and ∼5.82 M ⊙, respectively. The early-time photosphere velocity and the kinetic energy of the SN are, respectively, ∼1.89 × 104 km s−1 and ∼2.66 × 1052 erg, which are comparable to those of SNe Ic-BL and hypernovae (HNe), respectively. We suggest that the CSM of SN 2017dio might be from a luminous blue variable–like outburst or pulsational pair instability ∼1.2−11.4 yr prior to the SN explosion or binary mass transfer. Moreover, we find that its ejecta mass is larger than those of many SNe Ic-BL and that its 56Ni mass (M Ni) is approximately equal to the mean (or median) value of M Ni of SNe Ic-BL in the literature but lower than M Ni of prototype HNe (e.g., SN 1998bw and SN 2003dh).