The invention discloses a catalyst injection method and a catalyst injection device. A catalyst to be injected is placed in a container; the catalyst is injected into a riser reactor from an injection pipe which forms an angle of 0 to 70 DEG C with a horizontal direction by using rising gas; and the catalyst is injected into the riser reactor from a radical or tangent line direction. The reaction temperature, activity of the catalyst and the flexibility of regulation of an agent to oil ratio are increased and the yield of a target product is increased.