The invention provides a high-alloy steel titanium composite plate vacuum electron beam assembly soldering and sealing method. According to the high-alloy steel titanium composite plate vacuum electron beam assembly soldering and sealing method, a concave-convex structure catching groove assembly technical scheme is proposed to be combined with a before-welding baking and preheating scheme, and the technical problem that the weld seam of high-alloy steel titanium composite blanks cracks easily is solved. Stable production of a high-alloy steel titanium composite plate is realized. The rollingprocess of the steel titanium composite blank produced through the method is stable and smooth. The flaw detection results of rolled plate blanks are all qualified. All the properties of the rolled plate blanks are far higher than the properties required by users. A powerful technical support is provided for expanding stable production of high-quality high-alloy steel titanium products.