This study investigated the growth, indole-3-acetic acid (IAA) production, and remediation capability of the cyanobacteria Planktothrix spiroides sp. in real swine wastewater under various influencing factors, including wastewater concentration, L-tryptophan supplement, and pH level. Similar effects were observed on the biomass growth, IAA production, and remediation performance of the microalgae under these factors, confirming the major role of Planktothrix spiroides sp. in swine wastewater treatment. The optimal conditions for growth, IAA synthesis, and remediation of the microalgae were obtained at a 1.3X dilution rate, 0.2 g L^-1 of L-tryptophan addition, and a pH level of 9. Under these conditions, the highest biomass and IAA production were 64.1 ± 1.2 mg L^-1 d^-1 and 1.46 ± 0.05 μg mL^-1 d^-1, respectively. The optimized growth corresponded to high remediation efficiencies of 79.8 ± 2.4 % for COD removal (COD removal rate at 46.7 ± 1.4 mg O₂ L^-1 d^-1), 95.8 ± 0.1 % for TN removal (TN removal rate at 21.2 ± 0.01 mg N L^-1 d^-1), and 87.1 ± 0.5 % for TP removal (TP removal rate at 4.0 ± 0.01 mg P L^-1 d^-1). In contrast, the conditions, including undiluted swine wastewater, L-tryptophan concentration of up to 0.3 g L^-1 or higher, and acidic pH levels (pH 5 and 6), showed inhibitory impacts on the growth of Planktothrix spiroides sp. and subsequently its remediation and IAA production capabilities. Results from this study confirmed the potential of cyanobacteria Planktothrix spiroides sp. in swine wastewater remediation combined with biomass and IAA production. Applications in larger-scale systems are required in the future, with a primary focus on enhancing the IAA production capability of microalgae.