The invention discloses a combined installation method for door panel products, which comprises the following steps of: previously coating glue on the bottom toothed parts of first and second mosaic line frames, and coating glue on two toothed parts of connecting blocks; putting the glued first mosaic line frame into an outer frame, and turning over the outer frame to keep the outer surface of the first mosaic line frame at the lowest position; putting at least two connecting blocks, the toothed parts of which are glued, into the bottom of the first mosaic line frame so that the toothed part of one side of the connecting block is inserted into the toothed part of a first mosaic line; putting a panel core; putting the second mosaic line frame into the outer frame so that the toothed part of a second mosaic line is inserted into the toothed part of the other side of the connecting block; and clipping fixed points for preset time. By using the method, the assembly operation time is shortened; proved by experiments, the strength of toothed sticking is greatly higher than the holding force strength of a staple; and the method does not affect the appearance of the products.