The invention provides a negative electrode material, a negative electrode plate, a preparation method of the negative electrode plate and an all-solid-state lithium ion battery. The negative electrode material comprises coated lithium powder; silicon carbon powder; a conductive agent; and a solid electrolyte, wherein the coated lithium powder comprises lithium powder and a lithium-conducting coating layer coating at least one part of the outer surface of the lithium powder. In the negative electrode material, on one hand, the coated lithium powder is adopted, so that the activity of the coated lithium powder is greatly reduced compared with that of the lithium powder while the lithium can be effectively supplemented, no strict requirements for environment and equipment exist, the compatibility compared with the prior art is high, the production cost is lower, and meanwhile, the operation safety is greatly improved; and on the other hand, the solid electrolyte is added into the negative electrode material, so that the side reaction of the lithium powder and the solid electrolyte can be greatly reduced, the first coulombic efficiency can be effectively improved, and meanwhile, a lithium battery system has higher safety.