This study aimed to investigate the effects of various solvents (water, aqueous-methanol and aqueous-ethanol) and techniques (maceration (M), ultrasound-assisted extraction (UAE), ohmic-assisted extraction (OAE), and decoction – infusion (DI)) on extraction yield, pH, total phenolic contents (TPC), and antioxidant activity (DPPH radical scavenging activity (DRSA)) of flixweed seeds powder (FSP). Extraction systems were ranked by fuzzy-logic (inputs: extraction yield and time, TPC and DRSA). Water as a solvent in extraction process had the maximum yield, TPC and DRSA 6.49%; 141.598 mg GAE/100 mL and 72.91%, respectively. The difference between water and aqueous-ethanol was significant (p < 0.05). Values of pH of aqueous-methanol extract was significantly higher than other solvents. OAE and UAE achieved the highest (10.1%) and lowest (2.3%) extraction yields, respectively. Low temperature maceration showed the highest TPC and DRSA. Fuzzy-logic ranking based on expert's knowledge (30 experts) predicted the OAE with water as solvent to be score the highest rank in terms of overall efficiency.