Low temperature floor radiation heating system and the general design methods in programs are introduced.As the theory of the floor radiance heating system is different from the one of convective heat transfer,some proldems exist in cognition leading to the inconsistency of heat dissipation between practice and design of the low temperature floor radiance heating systen.Combined with formula existed in criterion,the ratio and the reduction of radiation heat dissipation of low temperature floor radiance heating system was worked out in different allowed floor surface average temperature tb and different indoor designed temperature tn,further more in shelter condition emphatically.It is reference to amount loss by sheltered floor area of low temperature floor radiation heating system design.