The invention discloses a cement-based permeable hardener. A preparation method of the cement-based permeable hardener comprises the following steps: reacting 300-320 parts of 18DEG Be fluosilicic acid with 15-25 parts of magnesium oxide for 2.5-3h, filtering the obtained reaction product, putting the obtained filtrate in a reaction kettle, adding 15-18 parts of aluminum hydroxide, carrying out a reaction at 70DEG C for 2.5-3h, adding 12-18 parts of lithium carbonate, heating above materials to 100DEG C, carrying out a reaction for 1-1.5h, pumping the obtained reaction solution to an elevated tank, filtering the reaction solution, evaporating the filtered solution, concentrating the evaporated solution, crystallizing the obtained concentrate, carrying out liquid-solid separation, drying the obtained solid to obtain white crystals, adding sodium alkyl benzene sulfonate, and stirring the white crystals and sodium alkyl benzene sulfonate until the white crystals and sodium alkyl benzene sulfonate are uniform in order to obtain the cement-based permeable hardener. The cement-based permeable hardener has the advantages of excellent quality and performances, low production cost, simple production device, solving of the environmental protection problem of phosphate fertilizer factories, waste gas recycling, and extremely good social and economic benefits.