State-owned capital stock is the result of national long-term investment and an important index to evaluate the state-owned economy productivity which accurately measures its scale and analyzes the value. It's also the quantity basis and necessary premise to affirm the function of state-owned enterprise, design the classified reform program, propel the mixed ownership reform, optimize the rational flowing system of the state-owned capital, and accomplish the strategic recombination of the state-owned economy under the background of state-owned-enterprises reform into capital management. State -owned fixed capital stock is the basis of measuring state-owned capital volume. The author tries to expand the application fields and range of the perpetual inventory system and ensure investment sequence and depreciation rate index by utilizing Newton's method and adopting total fixed capital formation and fractional depreciation rate. Through the estimation of the state-owned fixed capital stock from 1952 to 2014, the writer analyzes the reason of concave growth route under its presence, which provides important data supports and method inspiration for the subsequent research of state-owned capital stock and practice of state-owned-enterprises reform.