本课题研究的是不同CXCL12浓度下精子的趋化运动。首先将精子看作质点，选取了能够描述精子适应能力和弛豫时间的系统动力学方程，利用MATLAB模拟不同梯度浓度场下的趋化运动；然后把精子头部还原为球形刚体，研究其在鞭毛的推动力作用下，在低雷诺数环境中的平动和转动，进而导致的趋化性转向，以解释趋化物浓度对精子运动速率的影响；并将模型用MATLAB与实验数据进行了拟合。证明了浓度升高使运动轨迹曲率增大这一实验现象在计算模拟中的实用性；并以此为基础，提出了趋化物浓度升高会增加推动力的大小和其与头部中心轴线的夹角，且这两者都会对运动速率产生影响；利用两态模型等理论，假设了两两间的线性关系式，并给出了精子运动速率随趋化物浓度变化的理论公式，且其拟合出的曲线与实验数据基本相符，能够解释实验现象，证明了假设的合理性。

In this study, we focus on sperm chemotaxis at different CXCL12 concentrations. Firstly, the sperm is regarded as a particle, and we select the system dynamics equations, which can describing the adaptive ability and relaxation time of sperm, to simulate the chemotaxis in different concentration gradient fields by MATLAB. Then the head of sperm is restored to spherical rigid body, and the translation and rotation of the head under the driving force of flagellum in low Reynolds number environment are studied, which lead to chemotaxis, in order to explain the effect of chemotaxis concentration on sperm motility rate. And the model is fitted with the experimental data using MATLAB. We prove the practicability of the experimental phenomenon that the curvature of the trajectory increases with the increase of the concentration in the numerical simulation. On this basis, it is proposed that the increase of chemoattractant concentration will increase the magnitude of the driving force and the angle between the driving force and the central axis of the head, and both of them will affect the movement rate. Using the two-states model and other theories, the linear relationship between them is assumed, and the theoretical formula of sperm motility rate varying with chemoattractant concentration is given. The curve fitted accords with the experimental data, which can explain the experimental phenomena and prove the rationality of the hypotheses.