Abstract: The test method for fatigue thresholds and low fatigue crack growth rate are discussed and some improvements are made to the tentative ASTM test method for K and low fatigue crack growth rate. They are mainly as follows.1.The load-shedding parameters and the corresponding crack growth increaments for recommended procedures are: load-shedding ratio R = 5¹0%; K-decreassing gradient C=-0.2^- 0.05mm; crack growth interval a = 0. 25⁰.5mm.2.The relationship among specimen width, specimen type, load-shedding procedures and the maximum final crack length is presented.3. In data reduction, lg （da/dN） is recommended as the independent variable in the linear regression scheme to determine K or da/dN in stage region.4.A BASIC computer program for performing the test of fatigue thresholds and low fatigue crack growth rate in accordance with the proposed method is given.The improved method is more complete, reliable and applicable. It has been adopted in the national standard test method for fatigue crack growth rate.