The invention discloses a nickel alloy automobile starting motor planetary gear and a manufacturing method thereof. The nickel alloy automobile starting motor planetary gear is prepared from, by mass, 91-94% of diffusion alloy powder, 0.5-0.8% of C element powder, 0.5-0.9% of a paraffin lubricant and 4.3-8.0% of superfine nickel powder. According to the technical scheme, direct sintering and hardening of a high-nickel alloy powder metallurgy material are adopted, and the defects that in the prior art, after a planetary gear is sintered, deformation is caused through thermal treatment, the product precision cannot meet the requirement and a starting motor is high in noise and does not resist to abrasion are overcome successfully; due to the fact that no thermal treatment is needed, the gear precision is improved, a high energy consumption procedure is omitted, the cost is lowered, the product batch consistency is ensured, and batch production is easy to achieve.