Fan blade is a key component of wind turbine, and its crack fault is particularly common. The presence of cracks can cause damage to the blade or unit. Therefore, based on the tip timing principle and analysis method, a method of fan blade crack fault identification is proposed. Firstly, according to the principle of tip timing, the influence of blade crack on tip offset under load is analyzed, and the mathematical model between tip offset and tip offset time is established. Secondly, through the simulation analysis of blade tip offset degree in different states, combined with the mathematical model between different working condition parameters and tip offset time, the crack characteristic signal is identified. Finally, the results show that the recognition method proposed in this paper can successfully extract more than 92% of the characteristic signal of the crack, and can complete the extraction and analysis of the crack signal in real time, indicating that this method can realize the real-time recognition of the crack fault.