In order to obtain high energy density liquid propellant fuels and increase the payload of the launch vehicle， 20 different methyl-substituted bicyclobutyl derivatives were designed， and the influence of the structure of bicyclobutyl derivatives on performance was studied through theoretical calculations. Results show that with the increasing number of methyl substituents， the heat of formation and specific impulse of bicyclobutyl derivatives show a decreasing trend. When the substituent is para-substituted， its molecular stability is the best， and the heat of formation and specific impulse are larger， while the ortho-position substitution has a weakening effect on the heat of formation and specific impulse of bicyclobutyl derivatives. Among the designed compounds， the specific impulse of bicyclobutyl is the highest. When the mixing ratio of bicyclobutyl and liquid oxygen is 28.5∶71.5， the specific impulse can reach 304.52 s， and the main combustion products are CO（34.64%）， CO₂（13.89%） and H₂O （29.54%）. The comprehensive performance of all designed products is better than that of rocket kerosene. This study provides theoretical support for the design and synthesis of high-energy fuels.