Lithium lanthanum titanium oxide (LLTO) ceramic electrolyte possesses high ion conductivity and thermal stability, rendering it an ideal candidate for solid-state batteries. However, conventional methods of electrolyte preparation suffer from drawbacks such as poor interface contact, cumbersome procedures, and significant lithium loss during high-temperature sintering. To address these issues, a one-step sintering method to synthesize LLTO ceramic electrolytes with a straight-hole structure was developed. The micromorphology and electrochemical properties of one-step sintering prepared LLTO ceramic electrolytes were thoroughly investigated. The results reveal that this method enables the synthesis and sintering of LLTO ceramics with straight-hole structure in one step, thereby efficiently circumventing lithium loss during multiple sintering processes, enhancing the densification of LLTO ceramics, and reducing grain boundary resistance. Notably, LLTO ceramic electrolytes synthesized via one-step sintering method exhibit a high conductivity of 2.31×10-4 S/cm at room temperature. Moreover, Li/Li symmetric batteries assembled using this electrolytes demonstrate excellent Li+ deposition and stripping performance, which can be stable cycling for over 350 h at a current density of 0.1 mA/cm2. Furthermore, the all-solid-state lithium battery assembled with this electrolytes maintains a capacity retention rate of 94% after 200 cycles at a rate of 0.2 C, demonstrating the exceptional stability of straight-hole LLTO ceramics prepared via one-step sintering.