This paper presents an improved Grover searching algorithm which can automatically control the iterative processing when the number of target states is unknown.The probability of success of Grover searching algorithm depends on the number of iteration times and the number of the time of iterations relies on the number of target states.Therefore,it is hard to get the target state with high probability when the number of target states is unknown.To this question,the time com-plexity of conventional solution is high and the answer is non-deterministic.This paper shows an improved Grover searching algorithm,which is based on the sign for the phases of superposition state.Compared to existing research results,this algo-rithm can always stop the Grover iterations when the number of iteration times is optimal by the cost where just one more gate,and one more time Oracle call are needed to judge the sign of phase.%本文提出了利用相位门自动控制Grover搜索算法迭代次数的算法．Grover搜索算法最终得到目标分量的概率非常依赖于酉算子迭代的次数．迭代次数的计算依赖于目标分量的数量．因此当目标分量数未知时，该方法无法以高概率测量到目标分量．在以往的解决方案中需要较高的Oracle查询复杂度才能以一定概率得到目标分量的数量．本文提出了一种通过判断叠加态相位正负性，可自动控制Grover搜索算法迭代次数的方法．只需要添加一个判断相位的门电路，仅增加一次Oracle查询次数就可以精确的在最优迭代次数时停止Grover搜索算法，在搜索空间较小时可比原算法有更大的概率得到目标分量．
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