(K,Na)NbO₃-based ceramics (KNLNST ceramics) are a very promising type of lead-free piezoelectric materials. However, only limited studies were reported on them prepared by two-step sintering. Here, a comparison study was performed between two kinds of (K_0.4425Na_0.52Li_0.0375)(Nb_0.8825Sb_0.08Ta_0.0375)O₃ ceramics that were prepared by either conventional sintering (CS) or two-step sintering (TSS). It was found that TSS largely increases the relative density ρ° and piezoelectric coefficient d₃₃ from 95.0% and 363 pC/N of CS to 97.0% and 387 pC/N, respectively. KNLNST ceramics prepared by two kinds of sintering methods show significant differences between microstructure and domain structure. The KNLNST-CS ceramic has small grain sizes but distributed uniformly, and their domain patterns in most grains are simply a group or groups of parallel stripes. In contrast, the KNLNST-CS ceramic has a non-uniform grain-size distribution, with many large grains displaying broad bands, and existing fine strips.