The invention discloses a powder metallurgy friction material for railway passenger cars and a preparation method thereof, which comprises the following components by mass: 40-60 parts of copper powder, 8-20 parts of iron powder, 4-11 parts of tin powder, chromium alloy 3-8 parts of nickel powder, 3-4 parts of nickel powder, 1-3 parts of molybdenum alloy powder, 0.5-3 parts of phosphorus-iron alloy powder, 0.5-3 parts of manganese powder, 2-5 parts of titanium carbide, 2-5 parts of mullite , 1-3 parts of chromium oxide, 9-25 parts of graphite, and 1-4 parts of molybdenum disulfide. Copper powder, iron powder, tin powder, chromium alloy powder, nickel powder, manganese powder, molybdenum alloy powder and ferrophosphorus powder are mechanically alloyed, then the remaining components and binder are added for mixing; the mixture is cold pressed After forming, it can be degummed and then sintered without pressure at high temperature. The invention not only reduces the production cost of pressure sintering and restricts requirements on equipment and tooling, but also improves the continuous production efficiency and the stability of friction material performance.