The invention provides a nano suspension liquid concrete early strength agent and a preparation method thereof. The nano suspension liquid concrete early strength agent is prepared from transition metal element doped nano calcium metasilicate suspension liquid, the suspension liquid is mainly composed of nanometer silicon particles, the chemical structure of the nanometer silicon particles is aCaO.bAl2O3.cZnO.SiO2.6H2O, 1<=a<=2, 0.50<=b<=1, and 0.25<=c<=0.50. The nanometer silicon particles are prepared from soluble calcium salt, soluble silicate, soluble aluminum salt, soluble zinc salt and a high polymer dispersing agent. On the one hand, the early strength agent contains no chlorine salt and has no corroding function on steel bars in concrete; on the other hand, an extremely stable suspension liquid system is achieved, adding is facilitated, and the early strength agent can be evenly dispersed easily in the concrete preparation process. The early strength of concrete can be remarkably improved, the early strength effect on concrete adopting highly-doped mineral admixtures is especially obvious, the early strength agent is especially suitable for production of precast concrete components, and a steam maintenance process can be effectively reduced and even omitted.