The　high　oil　content　in　food　wastewater　often　limits　the　process　of　anaerobic　digestion　by　suppressing　microbial　activity　and　growth,　both　essential　for　organic　conversion　and　consequently　methane　production.　The　objective　of　this　study　was　to　optimize　biochar　dosage　for　enhancing　anaerobic　digestion　of　food　wastewater.　Thus,　the　synthetic　food　wastewater　containing　4　g/L　of　sodium　oleate　(oleate-Na)　and　an　initial　organic　concentration　of　5000　mg/L　COD　was　used.　Results　show　that　methane　production　was　severely　suppressed　during　the　anaerobic　digestion　of　food　wastewater　with　the　addition　of　oleate-Na,　reducing　cumulative　methane　yield　by　36.61　%.　The　inhibitory　effect　was　mitigated　with　biochar　addition,　particularly　at　5　g/L,　which　facilitated　oleate-Na　biodegradation　to　increase　the　cumulative　methane　production　by　196.50　%.　Sludge　characterization　and　microbial　analysis　indicated　that　adding　5　g/L　of　biochar　significantly　enhanced　biomass　growth　and　selectively　enriched　functional　bacteria,　such　as　Thermotogae　and　Bacteroidetes,　along　with　archaea　like　Methanoculleus　and　Methanosarcina,　promoting　hydrogenotrophic　methanogenesis　for　methane　production.　Nevertheless,　this　benefit　was　reduced　when　biochar　addition　was　increased　from　5　g/L　to　8　g/L,　likely　due　to　its　excessive　adsorption　of　compounds,　like　volatile　fatty　acids,　to　limit　further　methanogenesis.