The paper reviews the research progress on doping modifications of Ca3Co4O9 thermoelectric (TE) materials. Ca3Co4O9 is an excellent TE material that can convert thermal and electrical energy based on the Seebeck effect. However, its low electrical conductivity limits its TE performance, making the figure of merit (ZT) insufficient for practical applications. To enhance its TE properties, doping with various elements at Ca and Co sites is explored. This includes alkali (earth) metals, transition metals, rare earth metals, and even main group metals and non-metals. Doping increases carrier concentration, enhances electrical conductivity, and reduces thermal conductivity, thereby improving the TE properties. The paper discusses current challenges and future trends in doping modifications, providing a theoretical basis for further development and utilization of Ca3Co4O9 TE materials.The paper reviews the research progress on doping modifications of Ca3Co4O9 thermoelectric (TE) materials. Ca3Co4O9 is an excellent TE material that can convert thermal and electrical energy based on the Seebeck effect. However, its low electrical conductivity limits its TE performance, making the figure of merit (ZT) insufficient for practical applications. To enhance its TE properties, doping with various elements at Ca and Co sites is explored. This includes alkali (earth) metals, transition metals, rare earth metals, and even main group metals and non-metals. Doping increases carrier concentration, enhances electrical conductivity, and reduces thermal conductivity, thereby improving the TE properties. The paper discusses current challenges and future trends in doping modifications, providing a theoretical basis for further development and utilization of Ca3Co4O9 TE materials.