Compressed natural gas ship and emergency cut-off system thereof

The present invention provides a compressed natural gas ship and an emergency cut-off system thereof. The emergency cut-off system comprises a first gas detection module, a second gas detection module and a control module. The first gas detection module is arranged on the bow area and is used for detecting the natural gas concentration value of the bow area. When the natural gas concentration value reaches a preset detection value, the first gas detection module sends out a first early-warning signal. The second gas detection module is arranged on the upper-layer building area, and is used for detecting the natural gas concentration value of the upper-layer building area. When the natural gas concentration value reaches the preset detection value, the second gas detection module sends out a second early-warning signal. The control module is connected with the first gas detection module and/or the second gas detection module. The control module is capable of receiving the first early-warning signal and/or the