As a simple and efficient drainage gas recovery technology, plunger gas lift has been widely used in conventional gas wells with a depth of 4000m, but its application in deep wells is rarely reported in China. Therefore, combined with the field production and conventional plunger gas lift technology application experience, optimization of low pressure deep well plunger gas lift design methods, development of deep well plunger tools, optimization and improvement of the plunger process, a set of plunger gas lifting drainage gas recovery technology suitable for low pressure deep well has been formed. The results show that: on the basis of the conventional plunger gas lift design, the guiding chart of plunger starting pressure is established by introducing several factors such as wellbore inflow and casing pressure. Compared with the conventional method, the design method is more suitable for low pressure and low production deep well, and can greatly expand the application scope of the process. By changing the structure of the plunger, the self-sealing low leakage plunger is developed. Compared with the conventional plunger, the leakage during the operation of the plunger is reduced by 20% - 30% . Through the optimization design, when the ground process is reformed, both ends of the film valve are connected by wire, directly replacing the original temperature measurement /pressure sleeve conversion flange nipple, reducing the ground process, decreasing the ground pressure loss, improving the effect of the plunger lifting, and reducing the cost of reconstruction of about 10,000 yuan per well. Field tests were conducted for 15 well times, the process success rate was 100% , and the gas production of a single well was increased by more than 20% with the highest one of up to 6 times. Field test results show that low-pressure deep well plunger gas lift is a technology suitable for low-production deep well drainage gas production in Sichuan-Chongqing gas field, and can significantly improve the development effect and economic benefits of this type of gas wells.