The invention discloses a curtain body positioning mechanism of a rope-less window curtain. Two separating and connecting units are mainly used for controlling the positioning effect of a curtain body in the folding and unfolding processes. Each separating and connecting unit is provided with an axle, two brake blocks, a clutch wheel and two planetary gears, wherein the two brake blocks are connected to the circumferential edge of the axle in a spacing manner, so that a rolling slot is formed between the two brake blocks; the clutch wheel sleeves the axle and is provided with an inner ring tooth part surrounding the two brake blocks; the planetary gears are arranged in the rolling slot and are meshed with the inner ring tooth part of the clutch wheel; therefore, the planetary gears can be clamped with or separated from the brake blocks under the driving of the inner ring tooth part of the clutch wheel; when the planetary gears are clamped with the brake blocks, the curtain body cannot be driven to be positioned.