Abstract: Reusable rocket is a key technical path to achieving low-cost, high-frequency, and sustainable space transportation. The core challenges lie in power control, precise landing, thermal protection, and rapid maintenance, all of which highly rely on sensor systems with high reliability, high precision, and strong robustness. Based on this, focusing on the reusable rocket technology of the American SpaceX company, this paper systematically reviews the sensor systems applied in key stages such as flight control, attitude navigation, structural health management, and recovery landing. By comprehensively analyzing relevant research results and SpaceX's publicly available patents, the hardware specifications and technical architectures of core devices such as Inertial Measurement Units (IMUs), Global Positioning Systems (GPS), pressure and strain sensors in the Falcon 9 and Starship systems are deduced. The research shows that the sensor system based on SpaceX's technical route adopts a hybrid model of "high-reliability commercial components + highly customized software and hardware integration", achieving a multi-source sensor fusion network covering the entire life cycle, which can significantly reduce system costs while ensuring mission safety. In the future, emerging technologies such as intelligent integration, miniaturization, self-repair, and wireless power supply will further promote the evolution of sensor systems towards a closed loop of perception-cognition-decision-execution.