A substrate assembly and a method of bonding substrates are disclosed. The method includes steps of: providing two substrate; subjecting a connecting surface of each of the substrates to surface-modifying treatment to form surface-modified region respectively on each of the connecting surfaces; contacting the substrates in such a manner that the substrates are connected with each other through a physical interaction between the surface-modified regions; and laser irradiating and melting a portion of each of the connecting surfaces to form a respective bonding region, and solidifying the melted bonding regions of the substrates to bond the substrates together.