As an innovation and development of Marxist productivity theory in the context of socialism with Chinese characteristics entering a new era, new quality productivity not only profoundly reflects the tremendous changes in China’s economy and society but also serves as a significant driving force pushing forward China’s modernization. This theoretical innovation not only enriches and develops the Marxist theoretical treasury but also injects new vitality and momentum into China’s economic and social development. With the continuous advancement of China’s modernization, the development of newquality productivity inevitably promotes continuous changes in social relations, which require the safeguard and regulation of modern legal systems. In theory, the development of new quality productivity calls for the simultaneous innovation and deepening of modern legal theories. As the technological revolution and industrial transformation accelerate, traditional forms of productivity and social relations are undergoing unprecedented reshaping. The rapid development of emerging industries, the digital economy, artificial intelligence, and other fields poses new challenges and demands on legal construction. Therefore, modern legal theories must keep pace with the times, continuously incorporate the characteristics and needs of new quality productivity, and construct a solid legal framework and safeguard system for its development. This is both an inheritance and development of the Marxist view of the rule of law and a profound grasp of the laws governing legal construction in the process of China’s modernization. At the practical level, the development of new quality productivity cannot be separated from the comprehensive protection of the legal system. Innovating the allocation of production factors requires the legal system to clarify property rights ownership and facilitate efficient resource circulation. Maintaining an open and fair market competition environment necessitates the legal system to uphold market order and combat unfair competition. A sound scientific and technological management system requires the legal system to regulate research conduct and stimulate innovation vitality. A flexible and efficient innovation system requires the legal system to safeguard the conversion and application of innovation outcomes. A virtuous cycle of talent education and social security requires the legal system to ensure fairness and justice and promote social harmony. In terms of pathway selection, adhering to the guidance of Xi Jinping Thought on Socialism with Chinese Characteristics for a New Era is the fundamental principle for building the socialist legal system with Chinese characteristics. Under the strong leadership of the Communist Party of China, we must continuously improve the legislative, executive, and judicial systems, deepen the reform of the legal system’s operation, strengthen intellectual property protection, effectively protect the legitimate rights and interests of workers, and continuously optimize the business environment. These measures will not only provide robust legal safeguards for the development of new quality productivity but also lay a solid foundation for the smooth advancement of China’s modernization.