The invention discloses a power amplifier tube protection structure preventing a flange plate from being deformed during mounting and a forming method of the power amplifier tube protection structure.The power amplifier tube protection structure comprises a flange carrier plate (1) and a power amplifier tube with the flange plate (2). The lower surface of the flange plate (2) is welded and fixedto the upper surface of the flange carrier plate (1). The forming method comprises the steps that a copper carrier plate with the thickness being 4 mm is machined; the copper carrier plate is subjected to nickel-gold plating, namely Cu/Ep.Ni5Au0.5, and the flange carrier plate (1) is formed; the upper surface of the flange carrier plate (1) is brushed with a layer of low-temperature solder paste with the thickness being 0.12-0.15 mm; the flange plate (2) of the power amplifier tube is arranged on the flange carrier plate (1) and aligned up and down; the flange carrier plate (1) is arranged ona heating table; and S6, the temperature of the heating table is controlled to be 170 DEG C, and the flange plate (2) and the flange carrier plate (1) are subjected to heating welding. The flange plate of the power amplifier tube can be effectively prevented from being deformed during mounting, thus, the power amplifier tube is effectively prevented from being damaged, and great convenience is brought for mounting and application of the power amplifier tube.