The use of sensors and condition monitoring (CM) technologies to collect continuous real time measurements on wind turbine foundations as a means of detecting the existence of damage, identifying the location of damage, assessing the type and severity of damage, and estimating the remaining useful life (RUL) has been significantly growing in recent years. Quite often, considerable errors are reported between the measured structural modal properties through inspection and the simulated results based on CM-base dataset due to various "uncertainties". These uncertainties are usually related to design parameters, variable and complex offshore environments, complexity of the non-destructive testing (NDT) techniques, degree of detection of defects, etc. Neglecting the uncertainties involved in offshore wind structural monitoring may lead to collection of unreliable data and inaccurate evaluation of the system conditions, thereby inappropriate planning of inspection and preventative maintenance tasks. This project will provide an analytical reliability model to identify, analyse and evaluate the impacts of different types of uncertainties on condition assessment and monitoring of wind turbine foundation based on its sensor system, damage sensitive parameters, damage identification techniques, and system reliability index. The model will be then tested on a baseline offshore jacket platform structure and the probability of detection (POD), rate of false positive, true positive, false negative, and true negative are assessed.