The invention discloses vacuum drying equipment for synthesizing isooctyl salicylate and a vacuum drying method of the vacuum drying equipment. The vacuum drying equipment comprises a U-shaped plate, a feeding pump, an oil cylinder, a vacuum pump, an elliptical box, a double-cavity round block, a spiral hole channel, an electric heating box and a peristaltic pump. The structure is reasonable, the vacuum pump continuously exhausts the interior of the oval box until the vacuum standard is achieved, the heated boiling point can be reduced, water vaporization can be accelerated, and liquid in the spiral hole channel, the inlet guide pipe and the outlet guide pipe can be circularly heated to be in a high-temperature state; a motor is operated to drive the elliptical box connected through a rotating rod to rotate, so that the effect of rolling and stirring the synthetic substances is achieved, the drying progress can be accelerated, the dried substances can enter a material pipe, and the drying efficiency is improved. And the other feeding pump used for discharging is operated to discharge the dried substances to a centralized treatment position.