As for gas channeling happened in horizontal well during multiple thermal fluids huff and puff， the properties of thermal thickening gel（TTG）， containing cellulose ether as main component， such as static and dynamic gelling temperature， rheological and viscoelastic properties， plugging performance and enhancing oil displacement efficiency were measured. The results indicated that the gel static and dynamic gelling temperature of the TTG was 65℃ and 70℃， respectively. In environment of 80℃ and 0.5 Hz frequency， the elasticity modulus and viscous modulus of TTG with mass fraction of 1.5% could reach 30—40 Pa and 2.5—7.5 Pa， respectively. When adding 0.6 PV TTG aqueous solution with mass fraction of 1.5% ， the plugging ratio of gel to hot-water and multiple thermal fluid in core permeability of 13.08 μm2 and 3.2 μm2，respectively，was 99.7% and 98.85% ，respectively. The optimized gel injection was 0.6 PV， and the displacement efficiency could be improved by 16.2%. After thermal thickening gel sealing technology was used on site， the injection pressure increased by 2.5—4.5 MPa， and the producing wells around heat injection well were not affected during thermal fluid injection period. The well average daily oil production was 40 m3， and increased by 42.8% compared with that before injection thermal thickening gel work.