Abstract: The changes of bio-physical characters in anthers of thermo-sensitive genic male sterile rice ‘Annong S-1' under heat shock condition were studied. The results show that the totals of free amino acids, the contents of alanine and aspartic acid in anthers of ‘Annong S-1' through heat shock (38℃） are higher than those through low temperature (23℃）， and the contents of proline and soluble proteins through heat shock (38℃）are lower than those through low temperature (23℃). However, the changes are less in anthers of the control materials through heat shock (38℃) and low temperature (23℃). The changes affect possibly the normal meiosis of pollen mother cells and development of pollens, which leads to the sterility of pollens.