The purpose of this paper is to analyze the planning of the Treasury of the Massilians at Delphi. Through the analysis of the dimensional proportion of the building, the following conclusion was given. 1) As initial dimensions and proportions, the width of the treasury was given as 20 ft, the naos a square of 20 ft, and the depth of the pronaos one-third of the naos. 2) The proportional relationships between the dimensions are simple and exact. There is a tendency to use submultiple fraction. 3) Many dimensions are defined by successive system of proportion.