The invention discloses a constant-pressure linear perfuming system with double closed tanks. The constant-pressure linear perfuming system comprises the processes as follows: spices respectively enter a storage tank A and a storage tank B through an incoming control valve A1 and an incoming control valve B1; compressed air respectively enters the storage tank A and the storage tank B through a compressed air control valve A2 and a compressed air control valve B2; the storage tank A and the storage tank B are respectively connected with one end of a discharge control valve A5 and one end of a discharge control valve B5; the other ends of the discharge control valve A5 and the discharge control valve B5 are connected through a pipeline, sequentially pass through a flow meter, a linear control valve and a charging control valve C1, and are then connected with a roller. The constant-pressure linear perfuming system has the beneficial effects that the air subjected to pressure regulation and stabilization is utilized as a power source of the perfuming system; the linear control valve (a sliding window valve) has the characteristics of simple structure, no dead zone and accuracy control, so that feed liquid is constant in pressure; high flow and low flow can be accurately controlled; the defects such as perturbation, unstable flow control and hysteresis caused by a gear pump are completely eradicated; residual feed liquid of each batch is reduced; the investment in the perfuming system is lowered.