The invention relates to low-density oil-well cement, in particular to non-floating bead low-density oil-well cement. The invention solves the problems of low early strength, poor slurry flowability and stability and short service life of the traditional non-floating bead pulverized fuel ash low-density cement. The non-floating bead low-density oil-well cement comprises oil-well cement, pulverized fuel ash, an aldosterone sulfonate condensate dispersing agent, nano silicon ash stone and an early strength agent, and the mass content of SiO2 in the nano silicon ash stone is larger than or equalto 96 percent. The cement has good stability, good compactness, high early strength, long service life, good rheological property and controllable densification time and meets the requirement of a low-pressure stratum oil field cementation well on the performance of the cement.