The invention relates to a part in a mechanical device, in particular to a part in a rolling door or window. Each unit of the louver rolling door/window body disclosed by the invention is composed of a curtain piece main body 3 and a louver blade 1; the cross section of the louver blade 1 sectional material is an S-shaped structure; a tail wing 2 is arranged on the outer side of the lower hanging bottom of the S-shaped structure; the height of the tail wing 2 is equal to that of the middle part of the curtain piece main body 3 except the upper hanging part and the lower hanging part; the shape of the tail wing 2 is the same as that of the middle part of the curtain piece main body 3 except the upper hanging part and the lower hanging part; a side hanging part is formed in the middle of the S-shaped structure; the curtain piece main body 3 is provided with a middle part, an upper hanging part and a lower hanging part; the upper hanging part and the lower hanging part of the louver blade S are engaged; a hole is formed in the middle of the curtain piece main body 3; the lower hanging part of the curtain piece main body 3 and the upper hanging part of the louver blade 1 of the other unit are engaged so as to finish connection of two units; and after a plurality of units are connected in turn, the louver rolling door/window is formed. The louver rolling door/window body is convenient to overcome disadvantages of the prior art through the ingenious structure, and enables the rolling door/window to effectively ventilate and transmit light and have complete safety and privacy.