The invention discloses a space folding mechanism taking a six-rod mechanism as an extensible unit. The space folding mechanism comprises a six-rod mechanism, three-degree-of-freedom hinges and gaskets, wherein the six-rod mechanism comprises an octagonal support, an inclined side rod, a slider spring limiting telescopic rod and a slider spring combined constraint telescopic rod; the gaskets comprise a first gasket and a second gasket; the octagonal support is connected with one end of the inclined side rod through one three-degree-of-freedom hinge, the other end of the inclined side rod is connected with the first gasket and one end of the slider spring limiting telescopic rod through one revolute pair, the other end of the slider spring limiting telescopic rod is connected with one end of the slider spring combined constraint telescopic rod through another revolute pair, and the other end of the slider spring combined constraint telescopic rod is connected with the octagonal supportthrough the other three-degree-of-freedom hinge. The space folding of the mechanism is realized through folding twice, and the mechanism has the characteristics of large folding ratio, high stabilityand high reliability.