  To understand the interplay between nematic fluctuation and superconductivity
in iron-based superconductors, we performed a systematic study of the realistic
two-orbital Hubbard model by using the constrained-path quantum Monte Carlo
method. Our numerical results showed that the on-site nematic interaction
induces a strong enhancement of nematic fluctuations at various momentums,
especially at ($\pi$,$\pi$). Simultaneously, it was found that the on-site
nematic interaction suppresses the ($\pi$,0)/(0,$\pi$) antiferromagnetic order
and long-range electron pairing correlations for dominant pairing channels in
iron-based superconductors. Our findings suggest that nematic fluctuation seems
to compete with superconductivity in iron-based superconductors.
