Antiferroelectric materials have been extensively studied in the field of dielectric energy storage due to their ultra-high power density. Lead zirconate (PbZrO₃, PZO), as a prototype of antiferroelectric material, has been one of the most studied antiferroelectric materials, and research on enhancing energy storage performance of PZO-based materials is a hotspot of the current study. In this work, further improvement of the energy storage performance of PZO-based antiferroelectric thin films was realized by further doping small-radius Sr²⁺ into the A-site of the PZO perovskite structure on the basis of La³⁺-doped PZO. A series of antiferroelectric thin films of A-site La/Sr co-doped Pb_0.94-xLa_0.04Sr_xZrO₃ (Sr-PLZ-x, x = 0, 0.03, 0.06, 0.09, 0.12) were prepared by Sol-Gel method, and the effects of Sr²⁺ doping on the crystal structure and electrical properties such as ferroelectricity, energy storage, and fatigue properties of Sr-PLZ-x antiferroelectric films were systematically investigated. The results show that with the doping of Sr²⁺, the lattice constants are gradually reduced, and the saturation polarization of the films is first slightly increased and then maintained, but finally gradually decreased. The tolerance factors of Sr-PLZ-x films are reduced with increasing Sr²⁺ doping content, while the antiferroelectricities of the films are enhanced. Both the switching field and the breakdown strength are increased, resulting in an improved energy storage performance of Sr-PLZ-x films. At x=0.03, the energy storage performance of Sr-PLZ-x antiferroelectric film reaches the highest, with the energy storage density and efficiency are 31.7 J/cm³ and 71%, respectively. Meanwhile, the doping of Sr²⁺ also makes the fatigue characteristics of Sr-PLZ-x antiferroelectric films further improved. The x=0.12 antiferroelectric film exhibits only 3.4% and 2.7% degradation in energy storage density and energy storage efficiency after 10⁷ cycles. In summary, the method of A-site La/Sr co-doping can effectively improve the energy storage performance of PZO-based antiferroelectric films.