The supersymmetric grand unified theories (SUSY GUTs) are the promising models beyond the standard model for particle physics.
The standard SUSY GUTs predict that there exist the baryon-number violating processes, such as proton decay.
It is important to estimate quantum corrections on these processes in order to predict precise nucleon lifetime since there exists a large scale running between the GUT scale and 1 GeV where the nucleon matrix elements are calculated.
In this work, we have evaluated the GUT scale threshold corrections to the Wilson coefficients of the dimension-six baryon-number violating operators,
and then we have estimated the effect of the threshold corrections on the decay rate in the minimal and non-minimal SUSY SU(5) GUTs.
This talk will be based on our recent papers [arXiv:1503.08561] and [arXiv:1603.03568].