we compared the change of transcritome between the parents and their F1 hybrids showing different heterosis level and obtained the potential index for predicting the heterosis level between rice parental lines. Overall design: Examination of the profiles of transcription in young seedlings, young panicles and filling panicles of 4 parents and their 5 hybrids. R998 ,R308, WFB and RFB are the parental lines, and other lines are F1 hybrids. Their relationship is WY998 (WFB X R998), WY308 (WFB X R308), RY998 (RFB X R998), RY308 (RFB X R308), WR (WFB X RFB).