The utility model provides an LED illumination device which comprises a main body part and an LED luminous module, wherein the LED luminous module comprises a plurality of LEDs and a secondary optical lens. The secondary optical lens comprises a lens base and an optical processing module, wherein the optical processing module comprises a light incidence plane and a light-emitting surface. The light incidence plane is a cylindrical surface; the light-emitting surface comprises a curved surface light-emitting surface and inclined surface light-emitting surfaces; the curved surface light-emitting surface is a free curve surface which is formed by the motion of two curves which are perpendicular to each other on the direction of an optical axis; the two curves meet the following condition: X=A2Z2+A4Z4+...+A0, and X=B2Y2+B4Y4+...+B0; the tracks of the inclined surface light-emitting surfaces meet the following condition: Z=C1X+C0; the track of the fully reflecting side surface meets the following condition: Z=D1X+D0; the curved surface light-emitting surface in the light-emitting surface is arranged right above the light incidence surface to cover a whole light incidence surface; and the inclined surface light-emitting surfaces are symmetrically arranged at the two sides of the curved surface light-emitting surface, and are arranged right above the fully reflecting side surface to cover a whole fully reflecting side surface.