The invention provides a manufacturing method of an aluminum and phosphorus co-doping silicon nanometer crystal. The method comprises the following steps of step1), providing a substrate, and using alow pressure chemical vapor deposition method to deposit an aluminum and phosphorus doped silicon dioxide film on the substrate; step2), using a phase-splitting heat treatment technology to precipitate an aluminum and phosphorus doped silicon nanometer crystal in a phase-splitting mode in the silicon dioxide film, wherein the silicon nanometer crystal is inlaid in the silicon dioxide film; and step3), carrying out hydrogen passivation processing on the silicon dioxide film and the silicon nanometer crystal so as to remove the defects and the dangling bonds in the silicon dioxide film and the silicon nanometer crystal. In the invention, the aluminum and the phosphorus are used to carry out P-type and N-type doping so that the spectral range of silicon nanometer crystal luminescence is enlarged; photon absorption generated because of an Auger effect is reduced; and silicon nanometer crystal luminescence efficiency is increased. Simultaneously, the impurity doping amount of the silicon nanometer crystal is adjustable, crystallization quality is good and an ideal light source on a silicon substrate is acquired.