The invention relates to an engine idle speed control-based AMT (Automated Mechanical Transmission) vehicle start control method, which comprises the following steps of: a, starting an engine, shifting to a start gear, controlling the engine to maintain an idle speed state by an electric control AMT, gently stamping a throttle to send out a starting signal; b, after receiving the starting signal, controlling a power source to drive a clutch to a semi-combined point; c, controlling an engine speed to be in a range of 650-1300 rpm by the electric control AMT, and detecting whether the ROTATING speed of an output shaft is more than 50 rpm or not; d, controlling the torque limit value of the engine to BE increaseD from 40% to 100% progressively by the electric control AMT and controlling the power source to drive the clutch to gradually combine, detecting whether the clutch sliding rate is less than 5% or not and whether the rotating speed of the output shaft is more than 120 rpm or not; and e, stopping controlling the engine by the electric control AMT, and ending a vehicle start process. The engine idle speed-control based AMT vehicle start control method has the beneficial effects of reducing abrasion of the clutch, increasing the comfort and economy as much as possible on the premise of maintaining dynamic property, and the like.