The key to miniaturization of piezoelectric devices is to build high-performance fine-grained piezoceramics. Although the preparation of fine-grained ceramics can be achieved by hot press sintering or spark plasma sintering, complex processes, and high costs hinder the popularization of such technologies. In this work, a one-step conventional pressureless sintering technique based on partially amorphized nano-precursors has been proposed for low-cost preparation of submicron-structured ceramics. Using this technology, 0.36BiScO(3)-0.64PbTiO(3) ceramics with an average particle size of 170 nm and a relative density of 95% can be prepared at temperature as low as 900 degrees C, while the samples still have excellent piezoelectric properties (d(33) = 220 pC/N, g(33) = 40 x 10(-3) Vm/N). In the process of sintering partially amorphized nano-precursors, the initial densification rate is faster than the grain growth rate, which can be attributed to two effects promoting low temperature densification, one is the liquid phase sintering mechanism associated with the amorphous phase, and the other is the filling effect of small particles deposited at the grain boundaries. This work is simple and easy to implement, and it is expected to be extended to the preparation of other types of fine-grained ceramics.