The invention provides a method for preparing a technetium-99m tricarbonyl intermediate. The method comprises reacting a manganese carbonyl compound used as a carbon monoxide source with pertechnetate and water to obtain the technetium-99m tricarbonyl intermediate. The method for preparing a technetium-99m tricarbonyl intermediate in an embodiment of the invention can complete the preparation of the intermediate at atmospheric pressure and room temperature. The method is easy to operate, uses easily obtained raw materials, has a high labeling yield, and can be used to prepare various types of technetium tricarbonyl labeled probes.