It was the key problem that two-line hybrid rice met low temperature during seed production，which reduced the purity of seed.For technique of heating by water was a right measure adopted to depend against low temperature harm，multi-model for water and heat transfer was estimated by the principle of heat balance，which is checked by measured data and approved that the model is reliable.By inputting the different irrigation parameters，the results showed that along with net radiation，irrigation depth，water temperature at infalls and outfalls going up，air temperature at 20 cm gradually went up.To irrigate rationally，multi-factor interactions must be considered.In the present experiment，pollens fertility and self-fertilized seed set approved that the techniques were feasible and effective for safeguarding seed production of two-line hybrid rice.