本文基于灰色理论以及增量资本产出率和经济增长目标,确定了“十二五”时期我国投资规模的合理空间。结果表明,当投资率不小于23.7%时,我国投资与GDP构成的灰色系统才会保持稳定增长的状态;在既定经济增长目标和增量资本产出率波动空间的约束下,“十二五”时期我国投资率的合理空间为[27.91%,41.86%];目前我国实际投资率已经突破了合理投资率的上限,我国投资率急需进行向下调整。 Based on the gray theory, the incremental capital output rate and the goal of economic growth, this article has determined the reasonable space for China’s investment in the “12th Five-Year Plan” period. The results show that when the investment rate is not less than 23.7%, the gray system composed of investment and GDP in our country will maintain a steady growth. Under the constraints of the fixed economic growth target and incremental capital output volatility, The actual investment rate in our country has exceeded the upper limit of the reasonable investment rate and the investment rate in our country is in urgent need of downward adjustment.