A new fine-grained protocol analysis experiment teaching method based on Scapy is proposed to address the problems of coarse analysis granularity and poor teaching effects due to the interoperation between network applications in traditional protocol analysis experiments. Using Scapy, students can control the construction and sending sequence of protocol data units, making it a fine-grained network protocol analysis method as the interoperation unit in a packet. Taking the experimental project “TCP connection management” as an example, this paper describes in detail how to implement the fine-grained protocol analysis experiment teaching with Scapy. The teaching practice demonstrates that applying Scapy to the experimental teaching of protocol analysis encourages students to think deeply about network protocols through the packet interaction of both sides, resulting in remarkable teaching effects.