The invention relates to a thick bulk concrete elastic base and a construction method thereof. The construction method comprises: constructing a frame supporting column first, leaving a column cap on a rear grouting area, pre-embedding a column-side embedded part on the side wall of the frame supporting column, pre-embedding angle steel frames upwards on the circumference of the column cap of the frame supporting column, grouting the inside of the angle steel frames, and forming a column cap plane for assembling a spring vibration isolator, wherein the angle steel frames are higher than the column cap plane; welding a profile steel supporting frame outside the column cap, assembling the spring vibration isolator on the column cap plane and inside the profile steel supporting frame, laying an adjusting spacer on an outer scaffold on the circumference of the frame supporting column after the spring vibration isolator is in place, laying an upper pre-embedded steel plate above the profile steel supporting frame, supporting a die plate on the upper pre-embedded steel plate, assembling reinforcing steel bars and equipment embedded parts on the die plate, and casting concrete; and disassembling the die plate, assembling equipment, adjusting the elevation, and releasing the spring vibration isolator. The thick bulk concrete elastic base and the construction method solve the problems that an elastic base cannot be under stress in advance and a concrete bottom die is difficult to support, and prevent resonant damage of a reinforced concrete structure.