Studies on the gelation behaviors of the reactive blends of nylon1212 and functional elastomer were carried out. The results show that the curves of the storage modulus(G')-frequency (omega) exhibit a gel plateau in the low omega region, and the transition from liquid-like to solid-like viscoelastic behaviors emerges with the concentration of SEBS-g-MA increasing. There exist the gelation behaviors in the blending process similar to those of crosslinking polymer. Based on Winter's method, the gel point of blends is determined to be, phi(g) = 17.45 wt%, and the corresponding value of tan delta is 1.44. The gel index n calculated is 0.61 and the gel strength S (g) is 1.08 x10(4) Pa s(0.61). However, the non-reactive blends of nylon1212 and elastomer have no emergence of gelation behaviors. The morphology analysis shows that the gel point for the reactive blends is a threshold of cocontinuous morphology, and morphology analysis can also be a method to determine the gel point.