In today's fast-paced technology industry, microprocessors play an increasingly important role in a wide range of applications. However, verifying the correctness of complex microprocessor designs remains a significant challenge. To address this issue, a rigorous approach to microprocessor verification using the Universal Verification Methodology (UVM) is proposed. UVM provides a standardised and scalable approach to verifying digital designs, including microprocessors, and has been widely adopted in the industry. This research proposes a UVM-based verification framework for microprocessors that can identify and eliminate design errors early in the development cycle. The proposed approach covers functional verification, performance verification, and hardware-software co-verification. The effectiveness of the proposed approach is evaluated through a case study of a commercial microprocessor design, where the UVM-based verification framework successfully detected and resolved several design bugs. The results demonstrate the potential of the proposed rigorous approach to microprocessor verification using UVM to enhance the quality and reliability of microprocessor designs.