As the information age progresses rapidly, the demand for silicon photonic integrated circuits in optical communication, quantum precision measurement, artificial intelligence optical computing, and microwave photonics continues to grow. As an essential component of silicon photonic integrated circuits, optical isolators effectively prevent the backpropagation of optical signals, ensuring system stability and reliability. They are widely used in key technologies such as optical fiber communication, quantum communication, and laser systems. This paper reviews the research progress on on-chip integrated optical isolators, focusing on different implementation methods based on magneto-optic, acousto-optic, electro-optic, and nonlinear optical effects, discussing the advantages and challenges associated with each type. Finally, the paper explores future development directions and potential applications.