The utility model discloses a universal low-cost combined boat which comprises a main plate, two supporting bars and two protecting bars, wherein a straight groove is arranged at two side edges of a square plate, and two first short grooves vertical to the straight groove are arranged at the two side edges of the square plate; a raised line matched with the straight groove is arranged at the lower part of the supporting bars, and two second short grooves with two ends vertical to the raised line are arranged at the lower part of the supporting bars; the position of the first short grooves corresponds to that of the second short grooves, and the groove width is the same as the thickness of the protecting bars; and the protecting bars are inserted into the second short grooves at the same end of the two supporting bars and extend into the first short grooves of supporting edges of the square plate, the upper edges of the supporting bars are lower than the upper surfaces of the supporting bars, and the lower edges of the supporting bars are higher than the product laying surface of the main plate. The combined boat can not only increase the product loading amount in the boat, but also be convenient to clean and unload, have small storage space, improve the gas flow direction in the boat and improve the product quality.