The invention belongs to a vacuum soldering technology, and relates to a method for forming a welding substrate on the surface of microcrystalline glass. The method comprises the following steps: mixing tin powder and titanium powder with a prepared III type weak cotton solution to prepare a welding paste, coating the surface of the microcrystalline glass with the welding paste, and carrying out vacuum heating to form the welding substrate on the surface of the microcrystalline glass. The method has the advantages of low cost of required materials and devices, simple operation method, easy implementation, and good economic values and practical application values. The welding substrate formed through the method has the advantages of full wetting, diffusion into the microcrystalline glass, firm connection, high strength and good airtight property. A substrate material and a common welding solder can easily form reliable welding, so welding between the microcrystalline glass and different metals is realized, the welding stress is small, and the reliability is high.