Blockchain network topology reduction can assist cybersecurity researchers in understanding network structures and establishing protective mechanisms. However, existing topology reduction methods face two key challenges: limited attention to routing relationship information within the network and inaccurate node detection, making effective validation difficult. In the paper, we propose a measurement framework for blockchain network topology reduction. The framework leverages network protocol analysis to enhance the effectiveness of topology reduction. Through the three modules of node active discovery, node online verification and attribute resolution, and node route detection, we detect the node information and routing relationship information in the blockchain network, so as to perform topology reduction of the blockchain base network. We conducted experiments on two typical blockchain networks, Bitcoin and Ethereum, and the results demonstrate that our method is more efficient and comprehensive than comparison methods within the same time frame.