The nose landing gear generally has a bilateral symmetrical doors which are different from the main landing gear. The nose landing gear door opened when the civil aircraft enters the landing must interfere with the flow field and noise of the landing gear and reflect. In order to study the interference blocking effect of the nose landing gear door on the landing gear flow field and noise, firstly, a two-wheel landing gear model is used to confirm IDDES(Improved Delayed Detached Eddy Simulation) method and the FW-H(Ffowcs Williams-Hawkings) equation. On the basis of the accuracy and reliability of the numerical method, the flow field characteristics and far-field noise characteristics of the two models of the high-fidelity nose landing gear of a civil aircraft with and without doors are compared and analyzed. The flow evolution process near the doors and the influence of the doors on the far-field radiated noise are analyzed and studied. The calculation results show that because the windward face of the door is not straight, but slightly bends inward and has a certain angle with the free stream flow, it causes the local flow separation at the front of the doors, and then spreads to the whole area between the doors. At the same time, the doors on both sides block the trend of interference airflow spreading to the side of the cavity and impact the side edge of the cavity, block the pressure wave produced by the landing gear, weaken the sideline noise of the landing gear and form the phenomenon of acoustic interference.