The AL-700 series air leak tester adopts high-sensitivity differential pressure sensor with high test accuracy; adopts large-diameter air control valve, which has the advantages of fast inflation speed, good sealing performance, no heat generation, and long service life. The instrument has an intelligent test function. According to the characteristics of the differential pressure air leak tester, it can effectively eliminate the errors caused by temperature and deformation through the learning and correction function, realize short-time precision measurement, and greatly improve the test efficiency.