The invention discloses a rotary tillage, sowing, fertilizer application and chemical application multifunctional dry direct seeding machine. The machine comprises a machine frame, a rotary tillage device, a sowing device, a fertilizer application device, a chemical application device and a soil covering and compacting device. A shell is erected on the machine frame, the rotary tillage device is installed at the bottom of the shell, the fertilizer application device is installed at the upper end of the shell, the lower end of a fertilizer box in the fertilizer application device is provided with a fertilizer apparatus and a fertilizer application ditcher, a transmission and a suspension rack are installed in front of the fertilizer application device, the transmission outputs power and transmits the power to a gearbox through a transmission shaft, the gear box is arranged on a right side plate of the shell, then the gearbox transmits the power to the rotary tillage device on the lower portion, the chemical application device is installed behind the fertilizer application device, and the sowing device and the soil covering and compacting device are sequentially installed on the portion, behind the shell, of the machine frame. The machine is simple and reasonable in structure, the work mode integrating rotary tillage, fertilizer application, sowing, chemical application and other functions is used, the work efficiency is high, and the technical problems that an existing rice direct seeding machine is simplex in function, low in efficiency and poor in work quality are effectively solved.