Natural gas separation is the main way for industrial production of helium,but the low helium content（mole fraction,the same as below） of natural gas in most gas fields in China causes that more than 95%of helium in China depends on imports.Aiming at the natural gas with low helium content（less than 0.5%）,a process scheme of extracting helium by combining low temperature and high pressure concentration,natural gas liquefaction and low temperature rectification was put forward.Take an ethane recovery plant（feed gas temperature is 50℃,feed pressure is 5.8 MPa,treatment capacity is 1000×10~4 m~3/d） as an example,the process scheme of extracting helium from low helium natural gas and co-producing liquified natural gas（LNG） was simulated by Aspen HYSYS software.On the premise of controlling the helium concentration multiple to 19.15,the key parameters of the low-temperature and high-pressure concentration device were analyzed,and the adaptability of the process flow to the content of CO,2, and nitrogen in the feed gas was studied.It is found that too high pressure in the concentration tower will lead to an increase in helium loss at the bottom of the tower,and too low pressure will lead to an increase in the power of the export gas compressor,so a reasonable tower pressure of3.8 MPa is set for this feed gas.The increase of the tray number in the concentration tower will increase the helium recovery rate,but the increase of helium recovery rate is not obvious when the tray number is greater than 16.When the CO,2, content of the feed gas is lower than 2%,the concentration tower will not form CO,2, frozen blockage.When the nitrogen content of feed gas is higher than 0.5%,it is necessary to denitrify the overhead gas to meet the quality standard of LNG production.