To investigate the structural performance of novel comb-type steel-concrete composite girder bridges (with a span of 8?40 m) and optimize their design schemes, this paper took the live load structural efficiency index as the indicator and comprehensively considered factors such as structural mechanical performance, engineering economy, and construction convenience. It also studied the mechanical performance of the negative bending moment zone and the seamless joint of the integral abutment using numerical simulation. The results show that ① for comb-type steel-concrete composite girder bridges with a span of 8?20 m, the three-girder scheme is recommended; for those with a medium span of 30?40 m, the four-girder scheme possesses structural and economic advantages, while the five-girder scheme offers advantages in construction convenience and transportation; ② The reasonable range of girder height for the novel composite girders is clarified; in the four-girder scheme, it is recommended that the height of the steel web for a 30 m span should be 600?800 mm; ③ The structural scheme of the negative bending moment zone using small-sized CL connectors exhibits excellent mechanical performance; ④ The force transmission path of the seamless joint in the integral abutment is clarified, and specific engineering design schemes are proposed.