To analyse basic properties for making packing batt according to doubling condition, packing batt yarn, of $300^D$, $900^D$, $3600^D$ made from DTY yarn $150^D$/48 were produced from KTDI. The results are as follows: The birefringence of the sample yarn increased with increasing the annealing temperature and denier. The initial modulus of the sample yarn decreased with increasing the annealing temperature and denier. The higher than annealing temperature of $160^{circ}C$, initial modulus of the sample are equilibrated. The strain recovery ratio of samples decreased with increasing the annealing temperature and denier. The lower than annealing temperature of $140^{circ}C$, strain recovery ratio of the sample are decreased Where the $900^D$, $3600^D$ yarns are at $100^{circ}C$ the specific bending rigidity value obtained is 0.65kgf/d but the twisted yarn (3,600) obtained 0.006 ($gfcm^2/tex^2$). However, where the heat temperature is $160^{circ}C$, specific bending rigidity value obtained 0.003($gfcm^2/tex^2$).