The invention discloses a riveting and positioning tool for a chassis of a cotton picker. The riveting and positioning tool comprises a bottom supporting platform, a mounting plate positioning seat, atransverse beam positioning seat, a first flange supporting seat, a second flange supporting seat, a first positioning half shaft, a second positioning half shaft and positioning assemblies, whereinthe mounting plate positioning seat and the transverse beam positioning seat are arranged on the bottom supporting platform, the mounting plate positioning seat and the transverse beam positioning seat extend in the width direction of the bottom supporting platform, the first flange supporting seat and the second flange supporting seat, wherein the first flange supporting seat and the second flange supporting seat are arranged at the end, close to the mounting plate positioning seat, of the bottom supporting platform, the first positioning half shaft is arranged at the top end of the first flange supporting seat, the second positioning half shaft is arranged at the top end of the second flange supporting seat, the mounting plate positioning seat, the first positioning half shaft and the second positioning half shaft are used for positioning a front bridge frame of the chassis of the cotton picker, and the positioning assemblies are correspondingly arranged between the first flange supporting seat and the transverse beam positioning seat and between the second flange supporting seat and the transverse beam positioning seat. According to the riveting and positioning tool for the chassis of the cotton picker, the requirements for machining equipment can be reduced, the machining period can be shortened, meanwhile, the riveting and welding efficiency can be effectively improved, the riveting and welding precision of workpieces can be guaranteed, and the labor intensity of workers can be reduced.