The present invention provides a process for preparing a tantalum powder with high specific capacity, which process comprising the steps of, in sequence, (1) a first reduction step: mixing tantalum oxide powder and a first reducing agent powder homogenously, and then carrying out reduction reaction in hydrogen and/or inert gas or vacuum atmosphere to obtain a tantalum suboxides powder; (2) a second reduction step: mixing the tantalum suboxides powder obtained from the step (1), in which impurities have been removed, and a second reducing agent powder homogenously, and then carrying out reduction reaction in hydrogen and/or inert gas or vacuum atmosphere to obtain a tantalum powder having high oxygen content; (3) a third reduction step: mixing the tantalum powder having high oxygen content obtained from the step (2), in which impurities have been removed, with a third reducing agent powder homogenously, and then carrying out reduction reaction in hydrogen and/or inert gas or vacuum atmosphere to obtain a tantalum metal powder suitable for capacitors; wherein after each reduction step, the oxidation product of reducing agent and the residual reducing agent are removed from the reaction product.