The invention provides a combined tightly-pressing device for strip steel splicing welding. The combined tightly-pressing device comprises tightly-pressing structures and upper elastic plates. The twotightly-pressing structures are located at the ends of two pieces of to-be-welded strip steel correspondingly. Each tightly-pressing structure comprises an upper pressing plate and a lower pressing plate. Each upper pressing plate and the corresponding lower pressing plate are located on two opposite planes, namely the upper plane and the lower plane, of the corresponding piece of strip steel. The two upper elastic plates are located at the positions, on the upper surfaces of the two pieces of strip steel, between the two tightly-pressing structures, and each upper elastic plate is detachablyconnected with the corresponding upper pressing plate. The invention further provides splicing welding equipment and method for strip steel splicing welding. By means of the combined tightly-pressingdevice and splicing welding equipment and method for strip steel splicing welding, it can be guaranteed that in the welding process, the lower surfaces of the left strip steel and the right strip steel are flush with each other all the time; the misalignment phenomenon of the strip steels is effectively reduced; a space can be reserved above a welding seam area; a welding device can be arranged and maintained conveniently; and the combined tightly-pressing device and the splicing welding equipment are simple in structure, and the splicing welding method is easy to implement.