A flame retardant containing phosphorus JCHP-2 was synthesized using hexachlorotriphosphazene(HCCP), oligochitosan(JCH) and爀thanol. Linen fabric was finished by the flame retardant. Effect of phosphorus content and reagent dosage on flame retardancy of the finished fabric was discussed, and the durability was also tested. The results showed that the finished linen fabric exhibited good flame retardancy, which can reach B1 level of GB/T 5455-1997 when the dosage of JCHP-2 reached 12% and the phosphorus content was 14.41%. B2 standard was still met after 10 cycles of soaping. Thermalgravimetric analysis showed that the finished fabric's initial decomposition temperature was lowered, and the residue at 800℃ increased from 6.57% to 25.89%. All the above results indicated that the linen fabric finished with JCHP-2 had good flame retardancy.