The invention relates to a wearable power-assisting flexible outer garment for lower limbs. The flexible power-assisting outer garment comprises an outer garment body, Bowden cable units, two linear traction units and a gait detection unit. Normal walking motion can be assisted when a human body wears the power-assisting flexible outer garment for lower limbs. The outer garment body is attached to the skin of the lower limbs or the surface of clothes; the Bowden cable units are distributed along the outer garment body; according to a signal of the gait detection unit, the linear traction units drive Bowden cables to pull and assist ankle joints and hip joints of the human body at appropriate moments. The two linear traction units are stacked together to be placed in a backpack, each linear traction unit pulls two sets of Bowden cable units to respectively pull the hip joints and the ankle joints of the lower limbs of the human body, so as to assist in the forward flexion of the hip joints and the downward flexion of the ankle joints to reduce acting forces required by Achilles tendon of feet and thighs and shanks to lift legs, thereby reducing energy consumption of corresponding muscles of the lower limbs of the human body and assisting the lower limes in moving.