Steam-based thermal enhanced oil recovery techniques are widely applied methods to unlock heavy oil and natural bitumen resources. In this paper, two oil-soluble surfactants, as a subset of chemical additives, are introduced to favor the in situ catalytic hydrothermal upgrading of heavy oil. The solubility, salt tolerance, and thermal stability of both surfactants are experimentally investigated. The surfactant-assisted catalytic hydrothermal treatment of heavy oil was carried out in a batch reactor with a stirrer coupled with a gas chromatography device. The outputs of heavy oil upgrading processes were evaluated by comprehensive analysis of SARA fractions and elemental and structural changes of crude oil. Moreover, the distribution of low-molecular-weight alkanes in saturates and alkyl benzenes in aromatics are examined by gas chromatography−mass spectroscopy (GC−MS). The results confirmed the synergistic effect of catalytic nanoparticles and surfactants on the destructive hydrogenation of fused polynuclear aromatic rings such that the contents of resins and asphaltenes were reduced by 12.5 and 43.3%, respectively. In addition, surfactants contributed to hydrogen addition and inhibition of carbon rejection processes such that the H/C ratio increased from 1.32 to 1.72 with improving hydrodesulfurization and hydrodenitrogenation processes. Moreover, the amphoteric surfactant significantly enhanced the emulsification potential of the steam phase by decreasing the interfacial tension (IFT) between heavy crude oil and the steam phase, which positively affects the steam chamber propagations and hence leads to the incremental oil recovery in case of field-scale applications. On the basis of the achieved laboratory-scale results, the surfactant is a promising steam additive for improving heavy oil production.