We use Jordan-Wigner transform and Bogoliubov theory to study specific heat of triangular chains. In the absence of external magnetic field,it shows that doublet-peak structure disappears gradually as specific heat of a frustration system increases,which is due to antiferromagenetic excitation of spins in dimer state. As frustration is set 0.2 and applied external magenetic field,disappearence of specific heat double structure is due to occurrence of long-range magnetic order.