Extreme weather conditions such as typhoon occur frequently in coastal areas, and the typhoon environment causes significant changes in sea environment. As floating offshore wind turbine (FOWT) are often partially or fully installed at dock. This paper presents a study of FOWT’s dynamic response during blade installation phase at dock under typhoon condition. The integrated numerical model of FOWT during installation phase at dock is established in the first place. Then the typhoon environment conditions and its corresponding load characteristics are formulated. Based on this, the dynamic response analysis of the FOWT system is carried out with the developed numerical model. And sensitivity study of sea conditions, blade installation number and blade installation angle are carried out. The research results show that: in typhoon environment, FOWT’s dynamic response is sensitive to wave condition, which mainly determines the required fender resistance stiffness; the change of installed blade number causes the change of wind load on FOWT, and changes the FOWT motion perpendicular to environment direction rather significantly; FOWT’s dynamic responses do not change much when blade mounting angle changes.