Objective To study the reliability of 3 indexes of upper limb H reflex in hemiplegic patients after stroke， including the maximum amplitude of H reflex and the ratio of maximum M wave（ Hmax/ Mmax）， Slope of H reflex regression line and slope ratio of M wave regression line（ Hslp / Mslp） and post-activation depression（ PAD）. To explore the correlation between the indexes and paitent clinical assessment， so as to select a reliable H-reflex measurement. Methods A total of 15 stroke convalescent hemiplegic patients hospitalized in the Department of Rehabilitation Medicine， Capital Medical University from January to August 2016 were recruited in this study. The flexor carpi radialis（ FCR） innervated by the median nerve of the hemiplegic side was examined by H-reflex for 2 consecutive days. The reliability of the three indexes was tested by intra-group correlation coefficient. At the same time， the clinical evaluation was carried out by using the modified Ashworth Spasm Scale（ MAS）， Fugl-Meyer Scale（ FMA） and Brunnstrom Staging. The correlation between the results of three H reflex test results and clinical evaluation was analyzed. Results Of the three measurements， Hmax/Mmax was the best measurement in reliability， with ICC of 0.88. The next was Hslp/Mslp （ICC=0.85）. The reliability of PAD was the lowest（ ICC=0.2）. There was no statistical correlation among Hmax/Mmax， Hslp/Mslp and clinical MAS， FMA， Brunnstrom staging. Conclusions The reliability of Hmax/Mmax and Hslp/Mslp on the affected side of FCR in post-stroke patients is the best， which can be used as a reliable index for H reflex measurements.