The invention provides a method which is simple and is convenient to operate for improving material overflowing at material opening a particle board air spreading machine. According to the method, theparticle board air spreading machine is adopted for spreading assembling, wherein the particle board air spreading machine comprises a spreading assembling box, and a positive pressure fan (1) supplies air to the front portion of the spreading assembling box through a horizontal air door (3) and a vertical air door (4) which are arranged in the middle of the front portion of the spreading box; anoutlet of a wood particle metering device is located in front of the top of the spreading assembling box; a negative pressure fan (10) is used for sucking air at the tail portion of the spreading assembling box through an upper air outlet door and a lower air outlet door at the upper portion and the lower portion of air balance plate (8) at the tail portion of the spreading assembling box; a plate blank conveying device (6) is arranged below the spreading assembling box; and the method for improving material overflowing at the material opening under the front portion of the spreading assembling box is performed in the way that the air volume Ynegative of the negative pressure fan and/or the air volume Ypositive of the positive pressure fan are adjusted to make the value of Ynegative larger than or equal to the value of Ypositive plus 6000m<3>/h.