The invention belongs to the technical field of gears, and discloses a novel straight gear transmission type, in particular to a high-strength, low-vibration and low-noise straight gear transmission mechanism. The high-strength, low-vibration and low-noise straight gear transmission mechanism is specifically characterized in that 1, the pressure angles of tooth profile curved surfaces on the two sides of each gear are not equal and the meshed side pressure angle alpha d and the non-meshed side pressure angle alpha c respectively, and the alpha d is larger than the alpha c; 2, the pressure angles and moduli of the meshed gears 1 and 2 are not equal, namely, alpha d1 is not equal to alpha d2, alpha c1 is not equal to alpha c2, and m1 is not equal to m2; 3, the gears are meshed outside nodes. When the addendum circle pressure angle alpha ad1of the meshed side of the gear 1 is smaller than the meshed angle alpha', meshing is achieved before the node; when the addendum circle pressure angle alpha ad2 of the gear 2 is smaller than the meshed angle, meshing behind the node is achieved. The high-strength, low-vibration and low-noise straight gear transmission mechanism has the advantage of transmission of both a dual-pressure-angle asymmetric gear and a node external gear; compared with conventional transmission that a straight gear cylindrical gear is meshed outside a node, the high-strength, low-vibration and low-noise straight gear transmission mechanism has the advantages that the carrying capacity is improved, the size is reduced, the weight is lowered, and the service life is prolonged; compared with conventional dual-pressure-angle asymmetric straight gear cylindrical gear transmission, the high-strength, low-vibration and low-noise straight gear transmission mechanism has the advantages of being small in vibration and low in noise.