Abstract: Agricultural machinery can improve operational efficiency, but it can also exacerbate emission of dust from farmland and cause environmental pollution．Taking corn harvesting and wheat cultivation process in Changping District, Beijing as research object, impact of agricultural machinery operation on emissions of PM_2.5, PM₁₀, and TSP particles in farmland was revealed．Results showed that during wheat cultivation stage, degree of influence of agricultural machinery operation on dust concentration in farmland was in descending order: straw chopping, rotary tillage, no till sowing, and traditional sowing．Total amount of particulate matter emitted by traditional cultivation mode was 4.6～6.7 times that of protective cultivation mode．Protective cultivation mode reduced number of cultivation steps, reduced number of times agricultural machinery was lowered, and fundamentally reduced farmland dust．