The invention relates to a continuous ester interchange reaction method and a reactor in the production process of natural vitamin E and phytosterin. The continuous ester interchange reaction method comprises the following steps: firstly, fully mixing a methanol solution containing sodium methoxide with neutral oil; heating the mixture to 50-85 DEG C; and secondly, continuously entering a tubular reactor for ester exchange reaction, wherein the stay time of materials in the tubular reactor is 0.72-1.88 hours. The reactor is a tubular reactor with a hollow round tube; the diameter of the round tube of the tubular reactor is 50-150 mm; no motion part and any static filler are arranged in the reactor, so that the equipment flow is remarkably simplified, energy sources are saved, the maintenance is reduced and the process is continuously and stably carried out. The flow pattern in the tubular reactor approaches to a piston flow and is far superior to a fully-mixed flow in a mixing tank, and thus the operation efficiency of the ester exchange reactor is greatly increased and the quality of products is excellent and stable.