Scaling of earthquake faults is important not only for earthquake physics but also seismic hazard assessment. There have been many studies about this topic. It is significant to compile, review, and discuss those studies. This work reviews the observations and modeling of scaling of fault parameters, including the fault length (L), fault width (W), fault area (A), average displacement (D_o), maximum displacement (D_max), seismic moment (M_o), and static stress drop (Δσ). Major issues for reviewing in this work are: (1) assumptions of constant Δσ, of earthquakes and self-similarity of faults; (2) the L- and W-models; (3) the L-D_o and L-D_max scaling relationships; (4) the M_o-D_o and M_o-D_max scaling relationships; (5) the D_o-A scaling relationships; (6) the M_o-A scaling relationships; (7) the L-W scaling relationship; (8) the M_o-L and M_o-W scaling relationships; and (9) modeling of the M_o-L scaling based on the one-dimensional spring-slider model in the presence of velocity-weakening friction.