Due to the existing environment and special properties of gas hydrate, the only way to recover in-situ gas hydrate is to depend on the pressure-temperature-preserving sampling technique. And the pressure-temperature-preserving sampling system is the most important equipment to get the real physical and chemical properties of gas hydrate. Through the research on pressure-temperature-preserving sampling system for gas hydrate for many years, a non-interference wire-line pressure-temperature-preserving undisturbed sampling drilling tool was designed to get seabed sediments and hydrates in non-diagenetic formations. The sampling tool was introduced about its structure and characteristics, and the functions and features of the key mechanisms for matching pressure-temperature-preserving system were presented. The paper also detailed the coring technology as well as offshore function test and the test results met the design requirements.