The invention discloses a titanium-molybdenum-nickel alloy composite board which is used for manufacturing a power plant chimney. The titanium-molybdenum-nickel alloy composite board comprises a titanium-molybdenum-nickel alloy board and a substrate steel board; the titanium-molybdenum-nickel alloy board is made of titanium-molybdenum-nickel alloy and prepared from, by weight, 0.2%-0.4% of molybdenum, 0.6%-0.9% of nickel, 0.08% of carbon, 0.15% of silicon, 0-0.015% of hydrogen, 0-0.2% of oxygen, 0.3% of ferrum and the balance titanium. According to the titanium-molybdenum-nickel alloy composite board, the structures of the titanium-molybdenum-nickel alloy board and the substrate steel board are more reasonable, the cost performance of the metal composite board for a power plant is improved, the life of the metal composite board is prolonged, the usage temperature is increased, the unit capacity is increased, the design requirements are completely met, and the economical effeciency is high. The invention further provides a manufacturing method of the composite board.