During the second gas hydrate trial production test， the deep-sea wellhead suction anchor technology was firstly applied in the Shenhu sea area， which provids stable wellhead support for horizontal gas hydrate production wells in shallow soft formations. Through the theoretical calculation and finite element analysis， the self-weight penetration depth and negative pressure demand in the process of suction anchor penetration are studied. At the same time， the construction technology of “step-by-step intermittent self-weight penetration， dragging and continuous negative pressure sinking” was adopted in site， which ensured the successful installation of the first domestically produced deep-sea wellhead suction anchor. The field practice results show that the theoretical calculation results are close to the actual construction situation， and the theoretical analysis can guide the installation of suction anchors at the wellhead. In addition， the penetration construction technology is featured of fast， efficient and safe. The indicators of the wellhead suction anchor installation reached the usage demand. It has referential value for the application of suction anchor technology in the fields of deep-sea oil and gas.