In this work, filter paper was proven to be suitable as the substrate for the preparation of dynamic mechanical analysis (DMA) testing specimens to predict the curing behavior of phenol-formaldehyde (PF) resin adhesives for its stability during the curing temperature span. With this method, the curing behavior of PF resin was monitored by DMA in tensile-torsion mode. With the strain curves, the onset of curing temperature of PF resin could be determined clearly. The curing degree of PF resin could be calculated by the integral area in strain curves. The method to combine storage modulus (G '), tan delta, and strain curves together could explain the curing behavior of PF resin more comprehensively than the commonly used method using only G ' and tan delta curves. The DMA test results of PF resin with different viscosity and with accelerator implied the reliability of this novelty method.