CaBi 2 Nb 2 O 9 thin film capacitors were fabricated on SrRuO 3 -buffered Pt(111)/Ti/Si(100) substrates by adopting a two-step fabrication process. This process combines a low-temperature sputtering deposition with a rapid thermal annealing (RTA) to inhibit the grain growth, for the purposes of delaying the polarization saturation and reducing the ferroelectric hysteresis. By using this method, CaBi 2 Nb 2 O 9 thin films with uniformly distributed nanograins were obtained, which display a large recyclable energy density W rec ~69 J/cm 3 and a high energy efficiency η ~82.4%. A superior fatigue-resistance (negligible energy performance degradation after 10 9 charge-discharge cycles) and a good thermal stability (from -170 °C to 150 °C) have also been achieved. This two-step method can be used to prepare other bismuth layer-structured ferroelectric film capacitors with enhanced energy storage performances.