In this talk, we first recall the research history on self-similar solutions of the incompressible Navier-Stokes Equations，and introduce our recent results in this direction, which are joint with Changxing Miao; Xiaoxin Zheng. Besides, I also introduce my recent result on regularity of weak solution to the general Leray system (critical case). This system is closely related to self-similar solutions of Navier-Stokes Equations.